研究者データベース

西野 吉則(ニシノ ヨシノリ)
電子科学研究所 光科学研究部門
教授

基本情報

所属

  • 電子科学研究所 光科学研究部門

職名

  • 教授

学位

  • 博士(理学)(大阪大学)

ホームページURL

科研費研究者番号

  • 40392063

J-Global ID

研究キーワード

  • コヒーレントX線光学   Coherent X-ray Optics   

研究分野

  • ナノテク・材料 / 光工学、光量子科学
  • エネルギー / 量子ビーム科学
  • ナノテク・材料 / ナノバイオサイエンス
  • ナノテク・材料 / ナノ材料科学

職歴

  • 2001年 - 2010年 理化学研究所 研究員
  • 2001年 - 2010年 Researcher,RIKEN
  • 1996年 - 2001年 高輝度光科学研究センター 職員(技術系)
  • 1996年 - 2001年 Technical Staff,Japan Synchrotron Radiation Research Institute
  • 1998年 - 2000年 Deutsches Elektronen-Synchrotron 客員研究員
  • 1998年 - 2000年 Guest Scientist,Deutsches Elektronen-Synchrotron

学歴

  •         - 1996年   大阪大学   理学研究科   物理学専攻
  •         - 1996年   大阪大学
  •         - 1993年   大阪大学   理学研究科   物理学専攻
  •         - 1993年   大阪大学
  •         - 1991年   東京理科大学   理学部   物理学科
  •         - 1991年   東京理科大学

所属学協会

  • 日本放射光学   日本物理学会   The Japanese Society for Synchrotron Radiation Research   The Physical Society of Japan   

研究活動情報

論文

  • Takashi Kimura, Akihiro Suzuki, Ying Yang, Yoshiya Niida, Akiko Nishioka, Masashi Takei, Jinjian Wei, Hideyuki Mitomo, Yasutaka Matsuo, Kenichi Niikura, Kuniharu Ijiro, Kensuke Tono, Makina Yabashi, Tetsuya Ishikawa, Tairo Oshima, Yoshitaka Bessho, Yasumasa Joti, Yoshinori Nishino
    Review of Scientific Instruments 91 8 083706 - 083706 2020年08月01日 [査読有り][通常論文]
  • Chi-Feng Huang, Wei-Hau Chang, Ting-Kuo Lee, Yasumasa Joti, Yoshinori Nishino, Takashi Kimura, Akihiro Suzuki, Yoshitaka Bessho, Tsung-Tse Lee, Mei-Chun Chen, Shun-Min Yang, Yeukuang Hwu, Shih-Hsin Huang, Po-Nan Li, Peilin Chen, Yung-Chieh Tseng, Che Ma, Tsui-Ling Hsu, Chi-Huey Wong, Kensuke Tono, Tetsuya Ishikawa, Keng S. Liang
    AIP Advances 10 055219 055219-1 - 055219-11 2020年05月20日 [査読有り][通常論文]
  • Suzuki A, Kimura T, Yang Y, Niida Y, Nishioka A, Tachibana T, Takei M, Tono K, Yabashi M, Ishikawa T, Oshima T, Bessho Y, Joti Y, Nishino Y
    Physical chemistry chemical physics : PCCP 2019年08月 [査読有り][通常論文]
  • Kentaro Kuga, Yosuke Matsumoto, Mario Okawa, Shintaro Suzuki, Takahiro Tomita, Keita Sone, Yasuyuki Shimura, Toshiro Sakakibara, Daisuke Nishio-Hamane, Yoshitomo Karaki, Yasutaka Takata, Masaharu Matsunami, Ritsuko Eguchi, Munetaka Taguchi, Ashish Chainani, Shik Shin, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Satoru Nakatsuji
    Science Advances 4 2 eaao3547  2018年02月23日 [査読有り][通常論文]
     
    A valence critical end point existing near the absolute zero provides a unique case for the study of a quantum version of the strong density fluctuation at the Widom line in the supercritical fluids. Although singular charge and orbital dynamics are suggested theoretically to alter the electronic structure significantly, breaking down the standard quasi-particle picture, this has never been confirmed experimentally to date. We provide the first empirical evidence that the proximity to quantum valence criticality leads to a clear breakdown of Fermi liquid behavior. Our detailed study of the mixed valence compound a-YbAlB4 reveals that a small chemical substitution induces a sharp valence crossover, accompanied by a pronounced non-Fermi liquid behavior characterized by a divergent effective mass and unusual T/B scaling in the magnetization.
  • T. Koyama, H. Yumoto, T. Kimura, A Suzuki, T. Kameshima, Y. Joti, K. Tono, N. Tani, T. Tachibana, Y. Konishi, Y. Bessho, Y. Nishino, M. Yabashi, H. Ohashi
    Microscopy and Microanalysis 24 294 - 295 2018年 [査読有り][通常論文]
  • Krishna P. Khakurel, Takashi Kimura, Hiroki Nakamori, Takumi Goto, Satoshi Matsuyama, Tomoya Sasaki, Masashi Takei, Yoshiki Kohmura, Tetsuya Ishikawa, Kazuto Yamauchi, Yoshinori Nishino
    JOURNAL OF SYNCHROTRON RADIATION 24 142 - 149 2017年01月 [査読有り][通常論文]
     
    X-ray science has greatly benefited from the progress in X-ray optics. Advances in the design and the manufacturing techniques of X-ray optics are key to the success of various microscopic and spectroscopic techniques practiced today. Here the generation of apodized X-ray illumination using a two-stage deformable Kirkpatrick-Baez mirror system is presented. Such apodized illumination is marked by the suppression of the side-lobe intensities of the focused beam. Thus generated apodized illumination was employed to improve the image quality in scanning X-ray fluorescence microscopy. Imaging of a non-isolated object by coherent X-ray diffractive imaging with apodized illumination in a non-scanning mode is also presented.
  • Krishna P. Khakurel, Takashi Kimura, Hiroki Nakamori, Takumi Goto, Satoshi Matsuyama, Tomoya Sasaki, Masashi Takei, Yoshiki Kohmura, Tetsuya Ishikawa, Kazuto Yamauchi, Yoshinori Nishino
    Journal of Synchrotron Radiation 24 1 142 - 149 2017年01月01日 [査読有り][通常論文]
     
    X-ray science has greatly benefited from the progress in X-ray optics. Advances in the design and the manufacturing techniques of X-ray optics are key to the success of various microscopic and spectroscopic techniques practiced today. Here the generation of apodized X-ray illumination using a two-stage deformable Kirkpatrick-Baez mirror system is presented. Such apodized illumination is marked by the suppression of the side-lobe intensities of the focused beam. Thus generated apodized illumination was employed to improve the image quality in scanning X-ray fluorescence microscopy. Imaging of a non-isolated object by coherent X-ray diffractive imaging with apodized illumination in a non-scanning mode is also presented.
  • Satoshi Matsuyama, Hiroki Nakamori, Takumi Goto, Takashi Kimura, Krishna P. Khakurel, Yoshiki Kohmura, Yasuhisa Sano, Makina Yabashi, Tetsuya Ishikawa, Yoshinori Nishino, Kazuto Yamauchi
    SCIENTIFIC REPORTS 6 24801  2016年04月 [査読有り][通常論文]
     
    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick-Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions.
  • Jinjian Wei, Kenichi Niikura, Takeshi Higuchi, Takashi Kimura, Hideyuki Mitomo, Hiroshi Jinnai, Yasumasa Joti, Yoshitaka Bessho, Yoshinori Nishino, Yasutaka Matsuo, Kuniharu Ijiro
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 138 10 3274 - 3277 2016年03月 [査読有り][通常論文]
     
    We demonstrate that binary mixtures of small and large gold nanoparticles (GNPs) (5/15, 5/30, 10/30, and 15/30 nm in diameter) in the presence of a glucose-terminated fluorinated oligo(ethylene glycol) ligand can spontaneously form size-segregated assemblies. The outermost layer of the assembly is composed of a single layer of small-sized GNPs, while the larger-sized GNPs are located in the interior, forming what is referred to as a yolk/shell assembly. Time course study reveals that small and large GNPs aggregate together, and these kinetically trapped aggregations were transformed into a size-segregated structure by repeating fusions. A yolk/shell structure was directly visualized in solution by X-ray laser diffraction imaging, indicating that the structure was truly formed in solution, but not through a drying process.
  • Krishna P. Khakurel, Takashi Kimura, Yasumasa Joti, Satoshi Matsuyama, Kazuto Yamauchi, Yoshinori Nishino
    OPTICS EXPRESS 23 22 28182 - 28190 2015年11月 [査読有り][通常論文]
     
    Coherent diffraction imaging (CDI) is an established lensless imaging method widely used at the x-ray regime applicable to the imaging of non-periodic materials. Conventional CDI can practically image isolated objects only, which hinders the broader application of the method. We present the imaging of non-isolated objects by employing recently proposed "non-scanning" apodized-illumination CDI at an optical wavelength. We realized isolated apodized illumination with a specially designed optical configuration and succeeded in imaging phase objects as well as amplitude objects. The non-scanning nature of the method is important particularly in imaging live cells and tissues, where fast imaging is required for non-isolated objects, and is an advantage over ptychography. We believe that our result of phase contrast imaging at an optical wavelength can be extended to the quantitative phase imaging of cells and tissues. The method also provides the feasibility of the lensless single-shot imaging of extended objects with x-ray free-electron lasers. (C) 2015 Optical Society of America
  • Ryo Iida, Hitoshi Kawamura, Kenichi Niikura, Takashi Kimura, Shota Sekiguchi, Yasumasa Joti, Yoshitaka Bessho, Hideyuki Mitomo, Yoshinori Nishino, Kuniharu Ijiro
    LANGMUIR 31 14 4054 - 4062 2015年04月 [査読有り][通常論文]
     
    This study aims at the synthesis of Janus gold nanoparticles (Janus GNPs) with hydrophilic/hydrophobic faces by a simple ligand exchange reaction in an homogeneous system and at the elucidation of the self-assembled structures of the Janus GNPs in water. As hydrophilic surface ligands, we synthesized hexaethylene glycol (E6)-terminated thiolate ligands with C3, C7, or C11 alkyl chains, referred to as E6C3, E6C7, and E6C11, respectively. As a hydrophobic ligand, a butyl-headed thiolate ligand C4-E6C11, in which a C4 alkyl was introduced on the E6C11 terminus, was synthesized. The degree of segregation between the two ligands on the GNPs (5 nm in diameter) was examined by matrix-assisted laser desorption/ionization time-of fright mass spectrometry (MALDI-TOF MS) analysis. We found that the choice of immobilization methods, one-step or two-step addition of the two ligands to the GNP solution, crucially affects the degree of segregation. The two-step addition of a hydrophilic ligand (E6C3) followed by a hydrophobic ligand (C4-E6C11) produced a large degree of segregation on the GNPs, providing Janus-like GNPs. When dispersed in water, these Janus-like GNPs formed assemblies of similar to 160 nm in diameter, whereas Domain GNPs, in which the two ligands formed partial domains on the surface, were precipitated even when the molar ratio of the hydrophilic ligand and the hydrophobic ligand on the surface of the NPs was almost 1:1. The assembled structure of the Janus-like GNPs in water was directly observed by pulsed coherent X-ray solution scattering using an X-ray free-electron laser, revealing irregular spherical structures with uneven surfaces.
  • Marcus C. Newton, Mayu Sao, Yuta Fujisawa, Rena Onitsuka, Tomoya Kawaguchi, Kazuya Tokuda, Takahiro Sato, Tadashi Togashi, Makina Yabashi, Tetsuya Ishikawa, Tetsu Ichitsubo, Eiichiro Matsubara, Yoshihito Tanaka, Yoshinori Nishino
    NANO LETTERS 14 5 2413 - 2418 2014年05月 [査読有り][通常論文]
     
    The continuing effort to utilize the unique properties present in a number of strongly correlated transition metal oxides for novel device applications has led to intense study of their transitional phase state behavior. Here we report on time-resolved coherent X-ray diffraction measurements on a single vanadium dioxide nanocrystal undergoing a solid-solid phase transition, using the SACLA X-ray Free Electron Laser (XFEL) facility. We observe an ultrafast transition from monoclinic to tetragonal crystal structure in a single vanadium dioxide nanocrystal. Our findings demonstrate that the structural change occurs in a number of distinct stages attributed to differing expansion modes of vanadium atom pairs.
  • Takashi Kimura, Yasumasa Joti, Akemi Shibuya, Changyong Song, Sangsoo Kim, Kensuke Tono, Makina Yabashi, Masatada Tamakoshi, Toshiyuki Moriya, Tairo Oshima, Tetsuya Ishikawa, Yoshitaka Bessho, Yoshinori Nishino
    NATURE COMMUNICATIONS 5 3052  2014年01月 [査読有り][通常論文]
     
    Emerging X-ray free-electron lasers with femtosecond pulse duration enable single-shot snapshot imaging almost free from sample damage by outrunning major radiation damage processes. In bioimaging, it is essential to keep the sample close to its natural state. Conventional high-resolution imaging, however, suffers from severe radiation damage that hinders live cell imaging. Here we present a method for capturing snapshots of live cells kept in a micro-liquid enclosure array by X-ray laser diffraction. We place living Microbacterium lacticum cells in an enclosure array and successively expose each enclosure to a single X-ray laser pulse from the SPring-8 Angstrom Compact Free-Electron Laser. The enclosure itself works as a guard slit and allows us to record a coherent diffraction pattern from a weakly-scattering submicrometre-sized cell with a clear fringe extending up to a 28-nm full-period resolution. The reconstructed image reveals living whole-cell structures without any staining, which helps advance understanding of intracellular phenomena.
  • Takashi Kimura, Satoshi Matsuyama, Kazuto Yamauchi, Yoshinori Nishino
    Optics Express 21 8 9267 - 9276 2013年04月22日 [査読有り][通常論文]
     
    We propose a coherent x-ray zoom condenser lens composed of two-stage deformable Kirkpatrick-Baez mirrors. The lens delivers coherent x-rays with a controllable beam size, from one micrometer to a few tens of nanometers, at a fixed focal position. The lens is suitable for diffractive and scanning microscopy. We also propose non-scanning coherent diffraction microscopy for extended objects by using an apodized focused beam produced by the lens with a spatial filter. The proposed apodizedillumination method will be useful in highly efficient imaging with ultimate storage ring sources, and will also open the way to single-shot coherent diffraction microscopy of extended objects with x-ray free-electron lasers. © 2013 Optical Society of America.
  • Chainani, Ashish, Yamamoto, Ayako, Matsunami, Masaharu, Eguchi, Ritsuko, Taguchi, Munetaka, Takata, Yasutaka, Takagi, Hidenori, Shin, Shik, Nishino, Yoshinori, Yabashi, Makina, Tamasaku, Kenji, Ishikawa, Tetsuya
    Physical Review B 87 4 45108  2013年01月09日 [査読有り][通常論文]
  • Yoshihito Tanaka, Kiminori Ito, Takashi Nakatani, Rena Onitsuka, Marcus Newton, Takahiro Sato, Tadashi Togashi, Makina Yabashi, Tomoya Kawaguchi, Koki Shimada, Kazuya Tokuda, Isao Takahashi, Tetsu Ichitsubo, Eiichiro Matsubara, Yoshinori Nishino
    Journal of the Ceramic Society of Japan 121 1411 283 - 286 2013年 [査読有り][通常論文]
     
    Ultrafast time-resolved Bragg coherent X-ray diffraction (CXD) has been performed to investigate lattice dynamics in a thin crystal layer with a nanoscale thickness by using a SASE (Self-Amplified Spontaneous Emission)-XFEL (X-ray Free Electron Laser) facility, SACLA. Single-shot Bragg coherent diffraction patterns of a 100nm-thick silicon crystal were measured in the asymmetric configuration with a grazing exit using an area detector. The measured coherent diffraction patterns showed fringes extending in the surface normal direction. By using an optical femtosecond laser-pump and the XFEL-probe, a transient broadening of coherent diffraction pattern profile was observed at a delay time of around a few tens of picosecond, indicating transient crystal lattice fluctuation induced by the optical laser. A perspective application of the time-resolved Bragg CXD method to investigate small sized grains composing ceramic materials is discussed. © 2013 The Ceramic Society of Japan. All rights reserved.
  • Ashish Chainani, Ayako Yamamoto, Masaharu Matsunami, Ritsuko Eguchi, Munetaka Taguchi, Yasutaka Takata, Hidenori Takagi, Shik Shin, Yoshinori Nishino, Makina Yabashi, Kenji Tamasaku, Tetsuya Ishikawa
    PHYSICAL REVIEW B 87 4 2013年01月 [査読有り][通常論文]
     
    The tunability of bonding character in transition-metal compounds controls phase transitions and their fascinating properties such as high-temperature superconductivity, colossal magnetoresistance, spin-charge ordering, etc. However, separating out and quantifying the roles of covalency and metallicity derived from the same set of transition-metal d and ligand p electrons remains a fundamental challenge. In this study, we use bulk-sensitive photoelectron spectroscopy and configuration-interaction calculations for quantifying the covalency and metallicity in correlated compounds. The method is applied to study the first-order temperature(T-) dependent metal-insulator transitions (MITs) in the cubic pyrochlore ruthenates Tl2Ru2O7 and Hg2Ru2O7. Core-level spectroscopy shows drastic T-dependent modifications which are well explained by including ligand-screening and metallic-screening channels. The core-level metallic-origin features get quenched upon gap formation in valence band spectra, while ionic and covalent components remain intact across the MIT. The results establish temperature-driven Mott-Hubbard MITs in three-dimensional ruthenates and reveal three energy scales: (a) 4d electronic changes occur on the largest (similar to eV) energy scale, (b) the band-gap energies/charge gaps (E-g similar to 160-200 meV) are intermediate, and (c) the lowest-energy scale corresponds to the transition temperature TMIT (similar to 10 meV), which is also the spin gap energy of Tl2Ru2O7 and the magnetic-ordering temperature of Hg2Ru2O7. The method is general for doping-and T-induced transitions and is valid for V2O3, CrN, La1-xSrxMnO3, La2-xSrxCuO4, etc. The obtained transition-metal-ligand (d-p) bonding energies (V similar to 45-90 kcal/mol) are consistent with thermochemical data, and with energies of typical heteronuclear covalent bonds such as C-H, C-O, C-N, etc. In contrast, the metallic-screening energies of correlated compounds form a weaker class (V* similar to 10-40 kcal/mol) but are still stronger than van der Waals and hydrogen bonding. The results identify and quantify the roles of covalency and metallicity in 3d and 4d correlated compounds undergoing metal-insulator transitions. DOI: 10.1103/PhysRevB.87.045108
  • Javier Perez, Yoshinori Nishino
    CURRENT OPINION IN STRUCTURAL BIOLOGY 22 5 670 - 678 2012年10月 [査読有り][通常論文]
     
    Small-angle X-ray scattering (SAXS) of macromolecular systems in solution has become an obvious complement to high resolution structural studies. Using SAXS, structural hypotheses can be directly tested against experimental data in solution. Conformational changes or complex formation can be monitored, and help understanding structure-function relationships. Additionally, the reliability of the data has been much strengthened by on-line purification approaches. Moreover, when coherent X-rays are used for sample illumination, SAXS patterns become speckled and can provide electron-density maps directly by computational phase-retrieval methods. Furthermore, X-ray free-electron laser with femtosecond pulse duration will enable us to take time-frozen images of biomolecules in solution free from radiation damage. In this paper, recent experimental and methodological advances in both classical and coherent SAXS are reviewed.
  • J. W. Jung, J. S. Lee, N. Kwon, S. J. Park, S. Chang, J. Kim, J. Pyo, Y. Kohmura, Y. Nishino, M. Yamamoto, T. Ishikawa, J. H. Je
    REVIEW OF SCIENTIFIC INSTRUMENTS 83 9 93704  2012年09月 [査読有り][通常論文]
     
    A fast microtomography system for high-resolution high-speed imaging has been developed using bright monochromatic x-rays at the BL29XU beamline of SPring-8. The shortest scan time for microtomography we attained was 0.25 s in 1.25 mu m effective pixel size by combining the bright monochromatic x-rays, a fast rotating sample stage, and a high performance x-ray imaging detector. The feasibility of the tomography system was successfully demonstrated by visualization of rising bubbles in a viscous liquid, an interesting issue in multiphase flow physics. This system also provides a high spatial (a measurable feature size of 300 nm) or a very high temporal (9.8 mu s) resolution in radiographs. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4751853]
  • Yasumasa Joti, Takaaki Hikima, Yoshinori Nishino, Fukumi Kamada, Saera Hihara, Hideaki Takata, Tetsuya Ishikawa, Kazuhiro Maeshima
    NUCLEUS 3 5 404 - 410 2012年09月 [査読有り][通常論文]
     
    How is a long strand of genomic DNA packaged into a mitotic chromosome or nucleus? The nucleosome fiber (beads-on-a-string), in which DNA is wrapped around core histones, has long been assumed to be folded into a 30-nm chromatin fiber, and a further helically folded larger fiber. However, when frozen hydrated human mitotic cells were observed using cryoelectron microscopy, no higher-order structures that included 30-nm chromatin fibers were found. To investigate the bulk structure of mitotic chromosomes further, we performed small-angle X-ray scattering (SAXS), which can detect periodic structures in noncrystalline materials in solution. The results were striking: no structural feature larger than 11 nm was detected, even at a chromosome-diameter scale (similar to 1 mu m). We also found a similar scattering pattern in interphase nuclei of HeLa cells in the range up to similar to 275 nm. Our findings suggest a common structural feature in interphase and mitotic chromatins: compact and irregular folding of nucleosome fibers occurs without a 30-nm chromatin structure.
  • Marcus C. Newton, Yoshinori Nishino, Ian K. Robinson
    Journal of Applied Crystallography 45 4 840 - 843 2012年08月 [査読有り][通常論文]
     
    Coherent X-ray diffraction imaging has received considerable attention as a nondestructive method for probing material structure at the nanoscale. However, tools for reconstructing and analysing data in both two and three dimensions have lagged somewhat behind. Bonsu, the interactive phase retrieval suite, is the first software package that allows real-time visualization of the reconstruction of phase information in both two and three dimensions. It comes complete with an inventory of algorithms and routines for data manipulation and reconstruction. Bonsu is open source, is designed around the Python language (with C++ bindings) and is largely platform independent. Bonsu is made available under version three of the GNU General Public License and can be found at http://www.code.google.com/p/bonsu. © 2012 International Union of Crystallography. Printed in Singapore-all rights reserved.
  • Marcus C. Newton, Yoshinori Nishino, Ian K. Robinson
    Journal of Applied Crystallography 45 4 840 - 843 2012年08月 [査読有り][通常論文]
     
    Coherent X-ray diffraction imaging has received considerable attention as a nondestructive method for probing material structure at the nanoscale. However, tools for reconstructing and analysing data in both two and three dimensions have lagged somewhat behind. Bonsu, the interactive phase retrieval suite, is the first software package that allows real-time visualization of the reconstruction of phase information in both two and three dimensions. It comes complete with an inventory of algorithms and routines for data manipulation and reconstruction. Bonsu is open source, is designed around the Python language (with C++ bindings) and is largely platform independent. Bonsu is made available under version three of the GNU General Public License and can be found at http://www.code.google.com/p/bonsu. © 2012 International Union of Crystallography. Printed in Singapore-all rights reserved.
  • Masaharu Matsunami, Ashish Chainani, Munetaka Taguchi, Ritsuko Eguchi, Yasutaka Takata, Masaki Oura, Makina Yabashi, Kenji Tamasaku, Yoshinori Nishino, Tetsuya Ishikawa, Masashi Kosaka, Shik Shin
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 81 7 73702  2012年07月 [査読有り][通常論文]
     
    We use hard x-ray photoemission spectroscopy (HAXPES) to investigate the electronic structure of YbAl2, for which the Yb valence has not been consistently reported to date. The bulk sensitivity and the analytical simplicity provided by the Yb 3d core-level HAXPES allow a reliable determination of the mean valence of Yb ions. For YbAl2, it is evaluated to be +2.20, which remains nearly unchanged below 300 K. The Kondo resonance peak with an extremely high Kondo temperature (above 2000 K) is clearly identified in the valence-band spectra. The results indicate that a coherent Kondo state can be robust even in a nearly divalent system.
  • Masaharu Matsunami, Ashish Chainani, Munetaka Taguchi, Ritsuko Eguchi, Yasutaka Takata, Masaki Oura, Makina Yabashi, Kenji Tamasaku, Yoshinori Nishino, Tetsuya Ishikawa, Masashi Kosaka, Shik Shin
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 81 7 2012年07月 [査読有り][通常論文]
     
    We use hard x-ray photoemission spectroscopy (HAXPES) to investigate the electronic structure of YbAl2, for which the Yb valence has not been consistently reported to date. The bulk sensitivity and the analytical simplicity provided by the Yb 3d core-level HAXPES allow a reliable determination of the mean valence of Yb ions. For YbAl2, it is evaluated to be +2.20, which remains nearly unchanged below 300 K. The Kondo resonance peak with an extremely high Kondo temperature (above 2000 K) is clearly identified in the valence-band spectra. The results indicate that a coherent Kondo state can be robust even in a nearly divalent system.
  • Masaharu Matsunami, Ashish Chainani, Munetaka Taguchi, Ritsuko Eguchi, Yasutaka Takata, Masaki Oura, Makina Yabashi, Kenji Tamasaku, Yoshinori Nishino, Tetsuya Ishikawa, Masashi Kosaka, Shik Shin
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 81 7 2012年07月 [査読有り][通常論文]
     
    We use hard x-ray photoemission spectroscopy (HAXPES) to investigate the electronic structure of YbAl2, for which the Yb valence has not been consistently reported to date. The bulk sensitivity and the analytical simplicity provided by the Yb 3d core-level HAXPES allow a reliable determination of the mean valence of Yb ions. For YbAl2, it is evaluated to be +2.20, which remains nearly unchanged below 300 K. The Kondo resonance peak with an extremely high Kondo temperature (above 2000 K) is clearly identified in the valence-band spectra. The results indicate that a coherent Kondo state can be robust even in a nearly divalent system.
  • Yoshinori Nishino, Mikhail Eltsov, Yasumasa Joti, Kazuki Ito, Hideaki Takata, Yukio Takahashi, Saera Hihara, Achilleas S. Frangakis, Naoko Imamoto, Tetsuya Ishikawa, Kazuhiro Maeshima
    EMBO JOURNAL 31 7 1644 - 1653 2012年04月 [査読有り][通常論文]
     
    How a long strand of genomic DNA is compacted into a mitotic chromosome remains one of the basic questions in biology. The nucleosome fibre, in which DNA is wrapped around core histones, has long been assumed to be folded into a 30-nm chromatin fibre and further hierarchical regular structures to form mitotic chromosomes, although the actual existence of these regular structures is controversial. Here, we show that human mitotic HeLa chromosomes are mainly composed of irregularly folded nucleosome fibres rather than 30-nm chromatin fibres. Our comprehensive and quantitative study using cryo-electron microscopy and synchrotron X-ray scattering resolved the long-standing contradictions regarding the existence of 30-nm chromatin structures and detected no regular structure >11 nm. Our finding suggests that the mitotic chromosome consists of irregularly arranged nucleosome fibres, with a fractal nature, which permits a more dynamic and flexible genome organization than would be allowed by static regular structures. The EMBO Journal (2012) 31, 1644-1653. doi: 10.1038/emboj.2012.35; Published online 17 February 2012
  • 松山智至, 木村隆志, 中森紘基, 今井将太, 香村芳樹, 玉作賢治, 矢橋牧名, 石川哲也, 西野吉則, 山内和人
    プログラム予稿集 第11回X線結像光学シンポジウム 2011年11月 [査読無し][通常論文]
  • Development of an ultra-precise deformable mirror for hard X-ray nanofocusing
    Hiroki Nakamori, Satoshi Matsuyama, Takashi Kimura, Shouta Imai, Yoshiki Kohmura, Tetsuya Ishikawa, Yoshinori Nishino, Kazuto Yamauchi
    Program of 7th Handai Nanoscience and Nanotechnology International Symposium 2011年11月 [査読無し][通常論文]
  • Kazuto Yamauchi, Hidekazu Mimura, Takashi Kimura, Hirokatsu Yumoto, Soichiro Handa, Satoshi Matsuyama, Kenta Arima, Yasuhisa Sano, Kazuya Yamamura, Koji Inagaki, Hiroki Nakamori, Jangwoo Kim, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa
    JOURNAL OF PHYSICS-CONDENSED MATTER 23 39 394206  2011年10月 [査読有り][通常論文]
     
    We have constructed an extremely precise optical system for hard-x-ray nanofocusing in a synchrotron radiation beamline. Precision multilayer mirrors were fabricated, tested, and employed as Kirkpatrick-Baez mirrors with a novel phase error compensator. In the phase compensator, an at-wavelength wavefront error sensing method based on x-ray interferometry and an in situ phase compensator mirror, which adaptively deforms with nanometer precision, were developed to satisfy the Rayleigh criterion to achieve diffraction-limited focusing in a single-nanometer range. The performance of the optics was tested at BL29XUL of SPring-8 and was confirmed to realize a spot size of approximately 7 nm.
  • Hidekazu Mimura, Takashi Kimura, Hirokatsu Yumoto, Hikaru Yokoyama, Hiroki Nakamori, Satoshi Matsuyama, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 635 1 S16 - S18 2011年04月 [査読有り][通常論文]
     
    Hard X-rays are high-energy photons with extremely short wavelengths of the order of atomic distances. Their short wavelengths allow hard X-rays to be focused to nanometer sizes. This concept is simple; however, it is technically difficult to implement. For this reason, many physicists have been investigating X-ray focusing. In this study, we produce a single-digit nanometer sized hard X-ray focal spot using an ultraprecise multilayer mirror. Such extremely narrow hard X-ray beams can be used to achieve extremely high spatial resolutions in various X-ray microscopy techniques. Coupled with the high pulse powers of X-ray free-electron lasers, such nanofocusing optics have the potential to exceed the Schwinger limit. (C) 2010 Elsevier B.V. All rights reserved.
  • Rui Xu, Sara Salha, Kevin S. Raines, Huaidong Jiang, Chien-Chun Chen, Yukio Takahashi, Yoshiki Kohmura, Yoshinori Nishino, Changyong Song, Tetsuya Ishikawa, Jianwei Miao
    JOURNAL OF SYNCHROTRON RADIATION 18 2 293 - 298 2011年03月 [査読有り][通常論文]
     
    Since the first demonstration of coherent diffraction microscopy in 1999, this lensless imaging technique has been experimentally refined by continued developments. Here, instrumentation and experimental procedures for measuring oversampled diffraction patterns from non-crystalline specimens using an undulator beamline (BL29XUL) at SPring-8 are presented. In addition, detailed post-experimental data analysis is provided that yields high-quality image reconstructions. As the acquisition of high-quality diffraction patterns is at least as important as the phase-retrieval procedure to guarantee successful image reconstructions, this work will be of interest for those who want to apply this imaging technique to materials science and biological samples.
  • Rui Xu, Sara Salha, Kevin S. Raines, Huaidong Jiang, Chien-Chun Chen, Yukio Takahashi, Yoshiki Kohmura, Yoshinori Nishino, Changyong Song, Tetsuya Ishikawa, Jianwei Miao
    JOURNAL OF SYNCHROTRON RADIATION 18 293 - 298 2011年03月 [査読有り][通常論文]
     
    Since the first demonstration of coherent diffraction microscopy in 1999, this lensless imaging technique has been experimentally refined by continued developments. Here, instrumentation and experimental procedures for measuring oversampled diffraction patterns from non-crystalline specimens using an undulator beamline (BL29XUL) at SPring-8 are presented. In addition, detailed post-experimental data analysis is provided that yields high-quality image reconstructions. As the acquisition of high-quality diffraction patterns is at least as important as the phase-retrieval procedure to guarantee successful image reconstructions, this work will be of interest for those who want to apply this imaging technique to materials science and biological samples.
  • Rui Xu, Sara Salha, Kevin S. Raines, Huaidong Jiang, Chien-Chun Chen, Yukio Takahashi, Yoshiki Kohmura, Yoshinori Nishino, Changyong Song, Tetsuya Ishikawa, Jianwei Miao
    JOURNAL OF SYNCHROTRON RADIATION 18 293 - 298 2011年03月 [査読有り][通常論文]
     
    Since the first demonstration of coherent diffraction microscopy in 1999, this lensless imaging technique has been experimentally refined by continued developments. Here, instrumentation and experimental procedures for measuring oversampled diffraction patterns from non-crystalline specimens using an undulator beamline (BL29XUL) at SPring-8 are presented. In addition, detailed post-experimental data analysis is provided that yields high-quality image reconstructions. As the acquisition of high-quality diffraction patterns is at least as important as the phase-retrieval procedure to guarantee successful image reconstructions, this work will be of interest for those who want to apply this imaging technique to materials science and biological samples.
  • T. Ohtsuki, A. Chainani, R. Eguchi, M. Matsunami, Y. Takata, M. Taguchi, Y. Nishino, K. Tamasaku, M. Yabashi, T. Ishikawa, M. Oura, Y. Senba, H. Ohashi, S. Shin
    PHYSICAL REVIEW LETTERS 106 4 47602  2011年01月 [査読有り][通常論文]
     
    We study the surface and bulk electronic structure of the room-temperature ferromagnet Co:TiO2 anatase films using soft-and hard-x-ray photoemission spectroscopy with probe sensitivities of similar to 1 and similar to 10 nm, respectively. We obtain direct evidence of metallic Ti3+ states in the bulk, which get suppressed to give a surface semiconductor, thus indicating the difference in electronic structure between surface and bulk. X-ray absorption and resonant photoemission spectroscopy reveal Ti3+ electrons at the Fermi level (E-F) and high-spin Co2+ electrons occurring away from E-F. The results show the importance of the charge neutrality condition: Co2+ + V-O(2-) + 2Ti(4+) <-> Co2+ + 2Ti(3+) (V-O is oxygen vacancy), which gives rise to the elusive Ti 3d carriers mediating ferromagnetism via the Co 3d-O 2p-Ti 3d exchange interaction pathway of the occupied orbitals.
  • Takashi Kimura, Hidekazu Mimura, Soichiro Handa, Hirokatsu Yumoto, Hikaru Yokoyama, Shota Imai, Satoshi Matsuyama, Yasuhisa Sano, Kenji Tamasaku, Yoshiki Komura, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 81 12 123704  2010年12月 [査読有り][通常論文]
     
    In situ wavefront compensation is a promising method to realize a focus size of only a few nanometers for x-ray beams. However, precise compensation requires evaluation of the wavefront with an accuracy much shorter than the wavelength. Here, we characterized a one-dimensionally focused beam with a width of 7 nm at 20 keV using a multilayer mirror. We demonstrate that the wavefront can be determined precisely from multiple intensity profiles measured around the beamwaist. We compare the phase profiles recovered from intensity profiles measured under the same mirror condition but with three different aperture sizes and find that the accuracy of phase retrieval is as small as lambda/12. (C) 2010 American Institute of Physics. [doi:10.1063/1.3509384]
  • Yukio Takahashi, Yoshinori Nishino, Ryosuke Tsutsumi, Nobuyuki Zettsu, Eiichiro Matsubara, Kazuto Yamauchi, Tetsuya Ishikawa
    PHYSICAL REVIEW B 82 21 214102  2010年12月 [査読有り][通常論文]
     
    Hard x-ray diffraction microscopy enables us to observe thick objects at high spatial resolution. The resolution of this method is limited, in principle, by only the x-ray wavelength and the largest scattering angle recorded. As the resolution approaches the wavelength, the thickness effect of objects plays a significant role in x-ray diffraction microscopy. In this paper, we report high-resolution hard x-ray diffraction microscopy for thick objects. We used highly focused coherent x rays with a wavelength of similar to 0.1 nm as an incident beam and measured the diffraction patterns of a similar to 150-nm-thick silver nanocube at the scattering angle of similar to 3 degrees. We observed a characteristic contrast of the coherent diffraction pattern due to only the thickness effect and collected the diffraction patterns at nine incident angles so as to obtain information on a cross section of Fourier space. We reconstructed a pure projection image by the iterative phasing method from the patched diffraction pattern. The edge resolution of the reconstructed image was similar to 2 nm, which was the highest resolution so far achieved by x-ray microscopy. The present study provides us with a method for quantitatively observing thick samples at high resolution by hard x-ray diffraction microscopy.
  • S. Matsuyama, T. Wakioka, N. Kidani, T. Kimura, H. Mimura, Y. Sano, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Yamauchi
    OPTICS LETTERS 35 21 3583 - 3585 2010年11月 [査読有り][通常論文]
     
    We studied an imaging system consisting of an elliptical mirror and a hyperbolic mirror [i.e., one-dimensional (1D) Wolter optics] to realize an achromatic full-field hard x-ray microscopy with a resolution better than 50 nm. We report the performance of this 1D Wolter optical system when the mirrors were ultraprecisely figured by elastic emission machining. Experiments to form a demagnified image (demagnification factor of 385) of a 10 mu m slit were conducted at an x-ray energy of 11.5 keV at BL29XUL of SPring-8. The system could form a demagnified image with a resolution better than 50 nm over a 12.1 mu m field. (C) 2010 Optical Society of America
  • S. Matsuyama, T. Wakioka, N. Kidani, T. Kimura, H. Mimura, Y. Sano, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Yamauchi
    OPTICS LETTERS 35 21 3583 - 3585 2010年11月 [査読有り][通常論文]
     
    We studied an imaging system consisting of an elliptical mirror and a hyperbolic mirror [i.e., one-dimensional (1D) Wolter optics] to realize an achromatic full-field hard x-ray microscopy with a resolution better than 50 nm. We report the performance of this 1D Wolter optical system when the mirrors were ultraprecisely figured by elastic emission machining. Experiments to form a demagnified image (demagnification factor of 385) of a 10 mu m slit were conducted at an x-ray energy of 11.5 keV at BL29XUL of SPring-8. The system could form a demagnified image with a resolution better than 50 nm over a 12.1 mu m field. (C) 2010 Optical Society of America
  • Hard X-ray Imaging Optics with Elliptical mirrors and Hyperbolic Mirrors
    S. Matsuyama, T. Wakioka, H. Mimura, T. Kimura, N. Kidani, Y. Sano, Y. Nishino, K. Tamasaku, M. Yabashi, T. Ishikawa, K. Yamauchi
    SPIE Optics+Photonics, Technical Program 2010年08月 [査読無し][通常論文]
  • S. Matsuyama, M. Shimura, M. Fujii, K. Maeshima, H. Yumoto, H. Mimura, Y. Sano, M. Yabashi, Y. Nishino, K. Tamasaku, Y. Ishizaka, T. Ishikawa, K. Yamauchi
    X-RAY SPECTROMETRY 39 4 260 - 266 2010年07月 [査読有り][通常論文]
     
    Visualizing the elemental distributions of cells and tissues is of growing importance in biology and medical science because such data deepen our understanding of the behavior of metal-binding proteins and ions. Elemental mapping by X-ray fluorescence analysis with a hard X-ray nanobeam is very well suited for this purpose owing to its high sensitivity and high resolution. Using this technique, samples must be prepared without artifacts that are caused by treatments such as chemical fixation and staining procedures. In many studies of elemental mapping, sample preparation is not explicitly considered. To overcome this deficiency, we developed a cryo-scanning X-ray fluorescence microscope and installed it in the second experimental hutch of BL29XUL of SPring-8. We used it to observe frozen-hydrated cells that had been fixed by a quick-freezing technique to preserve elemental data of the living state at an X-ray energy of 11.5 keV. The distributions of K, Ca, Fe, Cu and Zn were successfully visualized. The distributions of these elements (especially those of K, Ca and Fe) differed from those in cells fixed with paraformaldehyde. Copyright (C) 2010 John Wiley & Sons, Ltd.
  • P. A. Bhobe, A. Chainani, M. Taguchi, T. Takeuchi, R. Eguchi, M. Matsunami, K. Ishizaka, Y. Takata, M. Oura, Y. Senba, H. Ohashi, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Takenaka, H. Takagi, S. Shin
    PHYSICAL REVIEW LETTERS 104 23 236404  2010年06月 [査読有り][通常論文]
     
    We investigate the electronic structure of chromium nitride (CrN) across the first-order magneto-structural transition at T-N similar to 286 K. Resonant photoemission spectroscopy (PES) shows a gap in the 3d partial density of states at the Fermi level and an on-site Coulomb energy U similar to 4.5 eV, indicating strong electron-electron correlations. Bulk-sensitive high-resolution (6 meV) laser PES reveals a clear Fermi edge indicating an antiferromagnetic metal below T-N. Hard x-ray Cr 2p core-level PES shows T-dependent changes across T-N which originate from screening due to coherent states as substantiated by cluster model calculations using the experimentally observed U. Electrical resistivity confirms an insulator above T-N (E-g similar to 70 meV) becoming a disordered metal below T-N. Thus, CrN transforms from a correlated insulator to an antiferromagnetic metal, coupled to the magnetostructural transition.
  • M. Okawa, M. Matsunami, K. Ishizaka, R. Eguchi, M. Taguchi, A. Chainani, Y. Takata, M. Yabashi, K. Tamasaku, Y. Nishino, T. Ishikawa, K. Kuga, N. Horie, S. Nakatsuji, S. Shin
    PHYSICAL REVIEW LETTERS 104 24 247201  2010年06月 [査読有り][通常論文]
     
    Electronic structures of the quantum critical superconductor beta-YbAlB4 and its polymorph alpha-YbAlB4 are investigated by using bulk-sensitive hard x-ray photoemission spectroscopy. From the Yb 3d core level spectra, the values of the Yb valence are estimated to be similar to 2.73 and similar to 2.75 for alpha- and beta-YbAlB4, respectively, thus providing clear evidence for valence fluctuations. The valence band spectra of these compounds also show Yb2+ peaks at the Fermi level. These observations establish an unambiguous case of a strong mixed valence at quantum criticality for the first time among heavy fermion systems, calling for a novel scheme for a quantum critical model beyond the conventional Doniach picture in beta-YbAlB4.
  • Yukio Takahashi, Hideto Kubo, Ryosuke Tsutsumi, Shigeyuki Sakaki, Nobuyuki Zettsu, Yoshinori Nishino, Tetsuya Ishikawa, Kazuto Yamauchi
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 616 2-3 266 - 269 2010年05月 [査読有り][通常論文]
     
    A method for evaluating the two-dimensional photon density distribution in focused hard X-ray beams is proposed and demonstrated in a synchrotron experiment at SPring-8. A synchrotron X-ray beam of 11.8 key is focused to a similar to 1 mu m spot by Kirkpatrick-Baez mirrors. The two-dimensional intensity distribution of the focused beam is derived by monitoring the forward diffracted intensity from an isolated silver nanocube with an edge length of similar to 150 nm positioned in the beam waist, which is two-dimensionally scanned. Furthermore, the photon density of X-rays illuminated onto the nanocube is estimated by utilizing coherent X-ray diffraction microscopy. This method is useful for evaluating the photon density distribution of hard X-ray beams focused to a spot size of less than a few micrometers. (C) 2009 Elsevier B.V. All rights reserved.
  • Soichiro Handa, Takashi Kimura, Hidekazu Mimura, Hirokatsu Yumoto, Satoshi Matsuyama, Yasuhisa Sano, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 616 2-3 246 - 250 2010年05月 [査読有り][通常論文]
     
    We describe a method for characterizing sub-10-nm X-ray beams using knife-edge scanning with dark-field geometry. Beam profile measurement by the conventional dark-field method is simulated numerically, and the signal intensity is found to depend strongly on the incident angle of the beam components. A numerical procedure to correct the dependence and to determine the actual beam profile is presented. (C) 2009 Elsevier B.V. All rights reserved.
  • Yukio Takahashi, Nobuyuki Zettsu, Yoshinori Nishino, Ryosuke Tsutsumi, Eiichiro Matsubara, Tetsuya Ishikawa, Kazuto Yamauchi
    NANO LETTERS 10 5 1922 - 1926 2010年05月 [査読有り][通常論文]
     
    Coherent diffraction microscopy using highly focused hard X-ray beams allows us to three-dimensionally observe thick objects with a high spatial resolution, also providing us with unique structural information, i.e., electron density distribution, not obtained by X-ray tomography with lenses, atom probe microscopy, or electron tomography. We measured high-contrast coherent X-ray diffraction patterns of a shape-controlled Au/Ag nanoparticle and successfully reconstructed a projection and a three-dimensional image of the nanoparticle with a single pixel (or a voxel) size of 4.2 nm in each dimension. The small pits on the surface and a hollow interior were clearly visible. The Au-rich regions were identified based on the electron density distribution, which provided insight into the formation of Au/Ag nanoboxes.
  • Yukio Takahashi, Hideto Kubo, Yoshinori Nishino, Hayato Furukawa, Ryosuke Tsutsumi, Kazuto Yamauchi, Tetsuya Ishikawa, Eiichiro Matsubara
    REVIEW OF SCIENTIFIC INSTRUMENTS 81 3 33707  2010年03月 [査読有り][通常論文]
     
    We developed a coherent x-ray diffraction microscopy (CXDM) system that enables us to precisely evaluate the electron density of an isolated sample. This system enables us to determine the dose per surface unit of x rays illuminated onto an isolated sample by combining incident x-ray intensity monitoring and the CXDM of a reference sample. By using this system, we determined the dose of x rays illuminated onto a nanostructured island fabricated by focused-ion-beam chemical vapor deposition and derived the electron density distribution of such a nanostructured island. A projection image of the nanostructured island with a spatial resolution of 24.1 nm and a contrast resolution higher than 2.3x10(7) electrons/pixel was successfully reconstructed.
  • M. Taguchi, A. Chainani, M. Matsunami, R. Eguchi, Y. Takata, M. Yabashi, K. Tamasaku, Y. Nishino, T. Ishikawa, S. Tsuda, S. Watanabe, C. -T. Chen, Y. Senba, H. Ohashi, K. Fujiwara, Y. Nakamura, H. Takagi, S. Shin
    PHYSICAL REVIEW LETTERS 104 10 106401  2010年03月 [査読有り][通常論文]
     
    The Magneli phase Ti4O7 exhibits two sharp jumps in resistivity with coupled structural transitions as a function of temperature at T-c1 similar to 142 K and T-c2 = 154 K. We have studied electronic structure changes across the two transitions using 7 eV laser, soft x-ray, and hard x-ray (HX) photoemission spectroscopy (PES). Ti 2p - 3d resonant PES and HX PES show a clear metallic Fermi edge and mixed valency above T-c2. The low temperature phase below T-c1 shows a clear insulating gap of similar to 100 meV. The intermediate phase between T-c1 and T-c2 indicates a pseudogap coexisting with remnant coherent states. HX PES and complementary calculations have confirmed the coherent screening in the strongly correlated intermediate phase. The results suggest the existence of a highly anomalous state sandwiched between the mixed-valent Fermi liquid and charge ordered Mott-insulating phase in Ti4O7.
  • Hidekazu Mimura, Soichiro Handa, Takashi Kimura, Hirokatsu Yumoto, Daisuke Yamakawa, Hikaru Yokoyama, Satoshi Matsuyama, Kouji Inagaki, Kazuya Yamamura, Yasuhisa Sano, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    NATURE PHYSICS 6 2 122 - 125 2010年02月 [査読有り][通常論文]
     
    Hard X-rays have exceptional properties that are useful in the chemical, elemental and structure analysis of matter. Although single-nanometre resolutions in various hard-X-ray analytical methods are theoretically possible with a focused hard-X-ray beam, fabrication of the focusing optics remains the main hurdle. Aberrations owing to imperfections in the optical system degrade the quality of the focused beam(1). Here, we describe an in situ wavefront-correction approach to overcome this and demonstrate an X-ray beam focused in one direction to a width of 7 nm at 20 keV. We achieved focal spot improvement of the X-ray nanobeam produced by a laterally graded multilayer mirror(2). A grazing-incidence deformable mirror(3) was used to restore the wavefront shape. Using this system, ideal focusing conditions are achievable even if hard-X-ray focusing elements do not achieve sufficient performance. It is believed that this will ultimately lead to single-nanometre spatial resolution in X-ray analytical methods.
  • Yoshinori Nishino, Yoshihito Tanaka, Makoto Okada, Motohiro Okaya, Yoshihito Uozaki, Kimihiko Nozaki, Makina Yabashi, Mitsuru Nagasono, Kensuke Tono, Hiroaki Kimura, Haruhiko Ohashi, Shinji Matsui, Tetsuya Ishikawa, Eiichiro Matsubara
    APPLIED PHYSICS EXPRESS 3 10 102701  2010年 [査読有り][通常論文]
     
    Emerging free-electron lasers (FELs) at short wavelengths open a new possibility for ultrafast microscopy of transient phenomena at high spatial resolution due to the ultrashort pulse duration. As a first step, we performed sub-picosecond snapshot imaging with extreme ultraviolet FEL by adopting a recently proposed holographic technique, holography with extended reference by autocorrelation linear differential operation (HERALDO). We point out that HERALDO enables efficient single-shot phase-contrast imaging by carefully designing the aperture size of the reference without sacrificing spatial resolution. The successful reconstruction of a test pattern from a single-shot hologram demonstrates an effective method of taking phase-contrast sub-picosecond snapshots. (C) 2010 The Japan Society of Applied Physics
  • Yoshinori Nishino, Yoshihito Tanaka, Makoto Okada, Motohiro Okaya, Yoshihito Uozaki, Kimihiko Nozaki, Makina Yabashi, Mitsuru Nagasono, Kensuke Tono, Hiroaki Kimura, Haruhiko Ohashi, Shinji Matsui, Tetsuya Ishikawa, Eiichiro Matsubara
    APPLIED PHYSICS EXPRESS 3 10 2010年 [査読有り][通常論文]
     
    Emerging free-electron lasers (FELs) at short wavelengths open a new possibility for ultrafast microscopy of transient phenomena at high spatial resolution due to the ultrashort pulse duration. As a first step, we performed sub-picosecond snapshot imaging with extreme ultraviolet FEL by adopting a recently proposed holographic technique, holography with extended reference by autocorrelation linear differential operation (HERALDO). We point out that HERALDO enables efficient single-shot phase-contrast imaging by carefully designing the aperture size of the reference without sacrificing spatial resolution. The successful reconstruction of a test pattern from a single-shot hologram demonstrates an effective method of taking phase-contrast sub-picosecond snapshots. (C) 2010 The Japan Society of Applied Physics
  • Yoshinori Nishino, Yoshihito Tanaka, Makoto Okada, Motohiro Okaya, Yoshihito Uozaki, Kimihiko Nozaki, Makina Yabashi, Mitsuru Nagasono, Kensuke Tono, Hiroaki Kimura, Haruhiko Ohashi, Shinji Matsui, Tetsuya Ishikawa, Eiichiro Matsubara
    APPLIED PHYSICS EXPRESS 3 10 2010年 [査読有り][通常論文]
     
    Emerging free-electron lasers (FELs) at short wavelengths open a new possibility for ultrafast microscopy of transient phenomena at high spatial resolution due to the ultrashort pulse duration. As a first step, we performed sub-picosecond snapshot imaging with extreme ultraviolet FEL by adopting a recently proposed holographic technique, holography with extended reference by autocorrelation linear differential operation (HERALDO). We point out that HERALDO enables efficient single-shot phase-contrast imaging by carefully designing the aperture size of the reference without sacrificing spatial resolution. The successful reconstruction of a test pattern from a single-shot hologram demonstrates an effective method of taking phase-contrast sub-picosecond snapshots. (C) 2010 The Japan Society of Applied Physics
  • Development of Achromatic X-ray Imaging System with 4 Aspherical Mirrors
    S. Matsuyama, M. Fujii, T. Wakioka, H. Mimura, Y. Sano, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Yamauchi
    Extended Abstracts of Second International Symposium on Atomically Controlled Fabrication Technology 2009年11月 [査読無し][通常論文]
  • Development of a Mirror Manipulator for Advanced Kirkpatrick-Baez Optics
    M. Fujii, S. Matsuyama, T. Wakioka, H. Mimura, Y. Sano, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Yamauchi
    Extended Abstracts of Second International Symposium on Atomically Controlled Fabrication Technology 2009年11月 [査読無し][通常論文]
  • Soichiro Handa, Hidekazu Mimura, Hirokatsu Yumoto, Takashi Kimura, Satoshi Matsuyama, Yasuhisa Sano, Kazuya Yamamura, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    JAPANESE JOURNAL OF APPLIED PHYSICS 48 9 96507  2009年09月 [査読有り][通常論文]
     
    To improve the performance of an X-ray nanobeam, we demonstrate the in situ determination and correction of the figure error of an elliptical mirror. The phase error profile on the mirror surface, which represents the figure error, is numerically reconstructed from the X-ray intensity distribution measured at the focal plane. The figure error is corrected by depositing a Pt film on the surface with subnanometer thickness controllability. Results of focusing experiments and subsequent analysis show a great improvement in focusing performance. (C) 2009 The Japan Society of Applied Physics
  • Soichiro Handa, Hidekazu Mimura, Hirokatsu Yumoto, Takashi Kimura, Satoshi Matsuyama, Yasuhisa Sano, Kazuya Yamamura, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    JAPANESE JOURNAL OF APPLIED PHYSICS 48 9 2009年09月 [査読有り][通常論文]
     
    To improve the performance of an X-ray nanobeam, we demonstrate the in situ determination and correction of the figure error of an elliptical mirror. The phase error profile on the mirror surface, which represents the figure error, is numerically reconstructed from the X-ray intensity distribution measured at the focal plane. The figure error is corrected by depositing a Pt film on the surface with subnanometer thickness controllability. Results of focusing experiments and subsequent analysis show a great improvement in focusing performance. (C) 2009 The Japan Society of Applied Physics
  • Soichiro Handa, Hidekazu Mimura, Hirokatsu Yumoto, Takashi Kimura, Satoshi Matsuyama, Yasuhisa Sano, Kazuya Yamamura, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    JAPANESE JOURNAL OF APPLIED PHYSICS 48 9 2009年09月 [査読有り][通常論文]
     
    To improve the performance of an X-ray nanobeam, we demonstrate the in situ determination and correction of the figure error of an elliptical mirror. The phase error profile on the mirror surface, which represents the figure error, is numerically reconstructed from the X-ray intensity distribution measured at the focal plane. The figure error is corrected by depositing a Pt film on the surface with subnanometer thickness controllability. Results of focusing experiments and subsequent analysis show a great improvement in focusing performance. (C) 2009 The Japan Society of Applied Physics
  • Yukio Takahashi, Yoshinori Nishino, Ryosuke Tsutsumi, Hideto Kubo, Hayato Furukawa, Hidekazu Mimura, Satoshi Matsuyama, Nobuyuki Zettsu, Eiichiro Matsubara, Tetsuya Ishikawa, Kazuto Yamauchi
    PHYSICAL REVIEW B 80 5 54103  2009年08月 [査読有り][通常論文]
     
    X-ray waves in the center of the beam waist of nearly diffraction limited focused x-ray beams can be considered to have amplitude and phase that are both almost uniform, i.e., they are x-ray plane waves. Here we report the results of an experimental demonstration of high-resolution diffraction microscopy using the x-ray plane wave of the synchrotron x-ray beam focused using Kirkpatrik-Baez mirrors. A silver nanocube with an edge length of similar to 100 nm is illuminated with the x-ray beam focused to a similar to 1 mu m spot at 12 keV. A high-contrast symmetric diffraction pattern of the nanocube is observed in the forward far field. An image of the nanocube is successfully reconstructed by an iterative phasing method and its half-period resolution is 3.0 nm. This method does not only dramatically improve the spatial resolution of x-ray microscopy but also is a key technology for realizing single-pulse diffractive imaging using x-ray free-electron lasers.
  • Takashi Kimura, Soichiro Handa, Hidekazu Mimura, Hirokatsu Yumoto, Daisuke Yamakawa, Satoshi Matsuyama, Kouji Inagaki, Yasuhisa Sano, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    JAPANESE JOURNAL OF APPLIED PHYSICS 48 7 72503  2009年07月 [査読有り][通常論文]
     
    A highly precise adaptive optical system that can be used in the hard X-ray region was developed. To achieve highly precise control of the wavefront shape, we discussed an optical system with a bendable mirror of deformation accuracy better than 0.4 nm RMS. Using the system, we demonstrated the controllability of the wavefront of a 15 nm hard X-ray nanobeam. The intensity profile of the wavefront-modified beam was in good agreement with the wave-optically calculated profile. (C) 2009 The Japan Society of Applied Physics DOI: 10.1143/JJAP.48.072503
  • Takashi Kimura, Soichiro Handa, Hidekazu Mimura, Hirokatsu Yumoto, Daisuke Yamakawa, Satoshi Matsuyama, Kouji Inagaki, Yasuhisa Sano, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    JAPANESE JOURNAL OF APPLIED PHYSICS 48 7 2009年07月 [査読有り][通常論文]
     
    A highly precise adaptive optical system that can be used in the hard X-ray region was developed. To achieve highly precise control of the wavefront shape, we discussed an optical system with a bendable mirror of deformation accuracy better than 0.4 nm RMS. Using the system, we demonstrated the controllability of the wavefront of a 15 nm hard X-ray nanobeam. The intensity profile of the wavefront-modified beam was in good agreement with the wave-optically calculated profile. (C) 2009 The Japan Society of Applied Physics DOI: 10.1143/JJAP.48.072503
  • Takashi Kimura, Soichiro Handa, Hidekazu Mimura, Hirokatsu Yumoto, Daisuke Yamakawa, Satoshi Matsuyama, Kouji Inagaki, Yasuhisa Sano, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    JAPANESE JOURNAL OF APPLIED PHYSICS 48 7 2009年07月 [査読有り][通常論文]
     
    A highly precise adaptive optical system that can be used in the hard X-ray region was developed. To achieve highly precise control of the wavefront shape, we discussed an optical system with a bendable mirror of deformation accuracy better than 0.4 nm RMS. Using the system, we demonstrated the controllability of the wavefront of a 15 nm hard X-ray nanobeam. The intensity profile of the wavefront-modified beam was in good agreement with the wave-optically calculated profile. (C) 2009 The Japan Society of Applied Physics DOI: 10.1143/JJAP.48.072503
  • M. Takizawa, Y. Hotta, T. Susaki, Y. Ishida, H. Wadati, Y. Takata, K. Horiba, M. Matsunami, S. Shin, M. Yabashi, K. Tamasaku, Y. Nishino, T. Ishikawa, A. Fujimori, H. Y. Hwang
    PHYSICAL REVIEW LETTERS 102 23 236401  2009年06月 [査読有り][通常論文]
     
    We have studied the valence redistribution of V in LaAlO3/LaVO3/LaAlO3 trilayers, which are composed of only polar layers grown on SrTiO3 (001) substrates, by core-level photoemission spectroscopy. We have found that the V valence is intermediate between V3+ and V4+ for thin LaAlO3 cap layers, decreases with increasing cap-layer thickness, and finally recovers the bulk value of V3+ at similar to 10 unit-cell thickness. In order to interpret these results, we propose that the atomic reconstruction of the polar LaAlO3 surface competes with the purely electronic V valence change so that the polar catastrophe is avoided at the cost of minimum energy.
  • Yukio Takahashi, Yoshinori Nishino, Hayato Furukawa, Hideto Kubo, Kazuto Yamauchi, Tetsuya Ishikawa, Eiichiro Matsubara
    JOURNAL OF APPLIED PHYSICS 105 12 124911  2009年06月 [査読有り][通常論文]
     
    Electromigration (EM) in a 1-mu m-thick Cu thin line was investigated by in situ coherent x-ray diffraction microscopy (CXDM). Characteristic x-ray speckle patterns due to both EM-induced voids and thermal deformation in the thin line were observed in the coherent x-ray diffraction patterns. Both parts of the voids and the deformation were successfully visualized in the images reconstructed from the diffraction patterns. This result not only represents the first demonstration of the visualization of structural changes in metallic materials by in situ CXDM but is also an important step toward studying the structural dynamics of nanomaterials using x-ray free-electron lasers in the near future. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3151855]
  • Yukio Takahashi, Yoshinori Nishino, Hidekazu Mimura, Ryosuke Tsutsumi, Hideto Kubo, Tetsuya Ishikawa, Kazuto Yamauchi
    JOURNAL OF APPLIED PHYSICS 105 8 83106  2009年04月 [査読有り][通常論文]
     
    High-flux coherent x rays are necessary for the improvement of the spatial resolution in coherent x-ray diffraction microscopy (CXDM). In this study, high-resolution CXDM using Kirkpatrick-Baez (KB) mirrors is proposed, and the mirrors are designed for experiments of the transmission scheme at SPring-8. Both the photon density and spatial coherence of synchrotron x rays focused by the KB mirrors are investigated by wave optical simulation. The KB mirrors can produce nearly diffraction-limited two-dimensional focusing x rays of similar to 1 mu m in size at 8 keV. When the sample size is less than similar to 1 mu m, the sample can be illuminated with full coherent x rays by adjusting the cross-slit size set between the source and the mirrors. From the estimated photon density at the sample position, the feasibility of CXDM with a sub-1-nm spatial resolution is suggested. The present ultraprecise figuring process enables us to fabricate mirrors for carrying out high-resolution CXDM experiments.
  • S. Matsuyama, M. Shimura, H. Mirnura, M. Fujii, H. Yumoto, Y. Sano, M. Yabashi, Y. Nishino, K. Tamasaku, T. Ishikawa, K. Yamauchi
    X-RAY SPECTROMETRY 38 2 89 - 94 2009年03月 [査読有り][通常論文]
     
    To visualize the distributions of trace elements in biological samples such as tissues and cells at high spatial resolution, we developed a scanning x-ray fluorescence microscope (SXFM) at SPring-8, using a Kirkpatrick-Baez mirror optics that enables achromatic and highly efficient focusing. To evaluate performance regarding its application to biological samples, the SXFM was used at x-ray energy of 15 keV to observe NIH/3T3 cells in which adenosine triphosphate (ATP) synthase beta (specifically localized at the mitochondria) were labeled with gold colloidal particles. Various elemental distributions were visualized at the single-cell level, including those for P, S, Cl, Ca, Fe, Cu, Zn and Au, and we obtained high-resolution elemental distribution maps by magnifying the labeled single mitochondrion. Maximum spatial resolution achieved in the experiments was sub-100 nm. Copyright (C) 2008 John Wiley & Sons, Ltd.
  • R. Eguchi, Y. Okamoto, Z. Hiroi, S. Shin, A. Chainani, Y. Tanaka, M. Matsunami, Y. Takata, Y. Nishino, K. Tamasaku, M. Yabashi, T. Ishikawa
    JOURNAL OF APPLIED PHYSICS 105 5 56103  2009年03月 [査読有り][通常論文]
     
    We study epitaxial NdNiO3 thin films on NdGaO3(001) single-crystal substrates grown using a pulsed-laser deposition method. The films show a clear first-order metal-insulator transition (MIT) at T-MI similar to 240 K, which is significantly higher than T-MI similar to 190 K in bulk NdNiO3. The x-ray reciprocal space map shows in-plane tensile and out-of-plane compressive strain, stabilizing the more distorted NdNiO3 thin films with the higher transition temperature. Hard x-ray photoemission shows changes across the MIT and the bandwidth-controlled charge-transfer gap opens due to the reduced p-d hybridization in the low-temperature insulating phase.
  • Yoshinori Nishino, Yukio Takahashi, Naoko Imamoto, Tetsuya Ishikawa, Kazuhiro Maeshima
    PHYSICAL REVIEW LETTERS 102 1 18101  2009年01月 [査読有り][通常論文]
     
    Coherent x-ray diffraction microscopy is a lensless phase-contrast imaging technique with high image contrast. Although electron tomography allows intensive study of the three-dimensional structure of cellular organelles, it has inherent difficulty with thick objects. X rays have the unique benefit of allowing noninvasive analysis of thicker objects and high spatial resolution. We observed an unstained human chromosome using coherent x-ray diffraction. The reconstructed images in two or three dimensions show an axial structure, which has not been observed under unstained conditions.
  • Hirokatsu Yumoto, Hidekazu Mimura, Soichiro Handa, Takashi Kimura, Satoshi Matsuyama, Yasuhisa Sano, Makina Yabashi, Yoshinori Nishino, Kenji Tamasaku, Tetsuya Ishikawa, Kazuto Yamauchi
    9TH INTERNATIONAL CONFERENCE ON X-RAY MICROSCOPY 186 2009年 [査読有り][通常論文]
     
    We have developed an advanced type of relative angle determinable stitching interferometry (RADSI) for hard x-ray nanofocusing mirrors. The surface metrology system consists of two types of optical interferometers. One is a microscope Michelson interferometer, which measures the local figure profile of the mirror surface, and the other is a large-area Fizeau interferometer, which determines the stitching angles between neighboring shots using a flat mirror. The surface figure profile of each of the one-shots and the stitching angles are measured at the same time. Precise measurement of local surface area and the stitching angles of 1 x 10(-8) rad order were achieved using the developed system. To demonstrate the accuracy of the developed measurement system, we measured an elliptically figured mirror for hard x-ray nanofocusing. The mirror's surface shape has a curvature radius of a few meters. As a result, measurement reproducibility and reliability of less than PV 3 nm was achieved by using a 25 urn focusing mirror.
  • Yukio Takahashi, Hideto Kubo, Hayato Furukawa, Kazuto Yamauchi, Eiichiro Matsubara, Tetsuya Ishikawa, Yoshinori Nishino
    9TH INTERNATIONAL CONFERENCE ON X-RAY MICROSCOPY 186 012060 2009年 [査読有り][通常論文]
     
    An incident x-ray flux monitor for coherent x-ray diffraction microscopy was developed. The intensities of x-rays passing through the sample were measured using an x-ray photodiode, with the simultaneous measurement of the x-ray diffraction intensities of the sample. As a result of the normalization of the x-ray diffraction intensities by the incident x-ray flux determined from the monitor, the fluctuation of the speckle intensities was successfully suppressed.
  • Nishino Yoshinori, Maeshima Kazuhiro, Imamoto Naoko, Hirohata Ryuta, Matsubara Eiichiro, Takahashi Yukio, Miao Jianwei, Ishikawa Tetsuya
    ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 65 S73  2009年 [査読有り][通常論文]
  • Yoshinori Nishino, Yukio Takahashi, Hideto Kubo, Hayato Furukawa, Kazuto Yamauchi, Kazuhiro Maeshima, Naoko Imamoto, Ryuta Hirohata, Eiichiro Matsubara, Tetsuya Ishikawa
    9TH INTERNATIONAL CONFERENCE ON X-RAY MICROSCOPY 186 1 - 3 2009年 [査読有り][通常論文]
     
    We report our recent activities on x-ray diffraction microscopy. We have been developing hardware and software instruments for efficient recording of high-quality coherent diffraction data. By using the microscope system developed, we carried out coherent diffraction measurement for various samples in materials science and biology, and succeeded in three-dimensional reconstruction revealing the internal structure.
  • Yoshinori NISHINO
    Nihon Kessho Gakkaishi 51 4 239 - 244 2009年 [査読有り][通常論文]
     
    Yoshinori NISHINO, 2009, 'Nanostructure Anaysis using Coherent X-ray Diffraction', <i>Nihon Kessho Gakkaishi</i>, vol. 51, no. 4, pp. 239-244
  • Kazuhiro MAESHIMA, Yoshinori NISHINO
    Seibutsu Butsuri 49 6 298 - 300 2009年 [査読有り][通常論文]
     
    Kazuhiro MAESHIMA, Yoshinori NISHINO, 2009, 'Three-Dimensional Visualization of a Human Chromosome Using Coherent X-ray Diffraction', <i>Seibutsu Butsuri</i>, vol. 49, no. 6, pp. 298-300
  • M. Matsunami, A. Chainani, M. Taguchi, R. Eguchi, Y. Ishida, Y. Takata, H. Okamura, T. Nanba, M. Yabashi, K. Tamasaku, Y. Nishino, T. Ishikawa, Y. Senba, H. Ohashi, N. Tsujii, A. Ochiai, S. Shin
    PHYSICAL REVIEW B 78 19 195118  2008年11月 [査読有り][通常論文]
     
    Hard x-ray photoemission and optical spectroscopies have been performed on YbS and Yb metal to determine the precise f-electron occupation. A comparison of the photoemission spectra with the energy-loss functions in bulk and surface, obtained from optical reflectivity, enables us to distinguish between the energy-loss satellite of Yb2+ peak and the Yb3+ multiplet. The results clearly indicate a purely divalent Yb state except for the surface of YbS which is altered by oxidation. We demonstrate that the present method is highly reliable in identifying the electronic structure and the mean valence in f-electron systems.
  • Yukio Takahashi, Hideto Kubo, Hayato Furukawa, Kazuto Yamauchi, Eiichiro Matsubara, Tetsuya Ishikawa, Yoshinori Nishino
    PHYSICAL REVIEW B 78 9 92105  2008年09月 [査読有り][通常論文]
     
    An element-specific coherent x-ray imaging technique using anomalous x-ray scattering in the hard x-ray region was first demonstrated. Coherent x-ray diffraction patterns of a sample composed of 500-nm-thick Ni and Cu layers were measured at incident x-ray energies around the Ni K absorption edge. Non-centersymmetric diffraction patterns due to anomalous scattering phenomenon in the hard x-ray region were observed. Symmetricity of the diffraction pattern was quantitatively analyzed by numerically simulating the x-ray wave field behind the sample position using the Rytov approximation. By calculating the difference between the intensities of reconstructed images of different energies, an image of the Ni layers could be derived although it was not enough to identify precisely. This method is widely applicable to nondestructive analysis of nanometer-scale elemental distribution of materials buried within thick and high-Z samples.
  • Hidekazu Mimura, Shinya Morita, Takashi Kimura, Daisuke Yamakawa, Weimin Lin, Yoshihiro Uehara, Satoshi Matsuyama, Hirokatsu Yumoto, Haruhiko Ohashi, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Hitoshi Ohmori, Kazuto Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 79 8 83104  2008年08月 [査読有り][通常論文]
     
    We present the design, fabrication, and evaluation of a large total-reflection mirror for focusing x-ray free-electron laser beams to nanometer dimensions. We used an elliptical focusing mirror made of silicon that was 400 mm long and had a focal length of 550 trim. Electrolytic in-process dressing grinding was used for initial-step figuring and elastic emission machining was employed for final figuring and surface smoothing. A figure accuracy with a peak-to-valley height of 2 nm was achieved across the entire area. Characterization of the focused beam was performed at BL29XUL of SPring-8. The focused beam size was 75 nm at 15 keV, which is almost equal to the theoretical size. (C) 2008 American Institute of Physics.
  • R. Eguchi, M. Taguchi, M. Matsunami, K. Horiba, K. Yamamoto, Y. Ishida, A. Chainani, Y. Takata, M. Yabashi, D. Miwa, Y. Nishino, K. Tamasaku, T. Ishikawa, Y. Senba, H. Ohashi, Y. Muraoka, Z. Hiroi, S. Shin
    PHYSICAL REVIEW B 78 7 75115  2008年08月 [査読有り][通常論文]
     
    The temperature (T)-dependent metal-insulator transition (MIT) in VO(2) is investigated using bulk sensitive hard-x-ray (similar to 8 keV) valence-band, core-level, and V 2p-3d resonant photoemission spectroscopies (PESs). The valence-band and core-level spectra are compared with full-multiplet cluster model calculations including a coherent screening channel. Across the MIT, V 3d spectral weight transfer from the coherent (3d(1)(C) under bar final) states at Fermi level to the incoherent (3d(0)+3d(1)(L) under bar final) states, corresponding to the lower Hubbard band, leads to gap formation. The spectral shape changes in V 1s and V 2p core levels as well as the valence band are nicely reproduced from cluster model calculations, providing electronic structure parameters. Resonant PES finds that the 3d(1)(L) under bar states resonate across the V 2p-3d threshold in addition to the 3d(0) and 3d(1)(C) under bar states. The results support a Mott-Hubbard transition picture for the first-order MIT in VO(2).
  • Nishino Yoshinori, Takahashi Yukio, Maeshima Kazuhiro, Imamoto Naoko, Matsubara Eiichiro, Ishikawa Tetsuya
    ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES 64 C118  2008年08月 [査読有り][通常論文]
  • Yukio Takahashi, Hayato Furukawa, Hideto Kubo, Kazuto Yamauchi, Yoshinori Nishino, Tetsuya Ishikawa, Eiichiro Matsubara
    SURFACE AND INTERFACE ANALYSIS 40 6-7 1046 - 1049 2008年06月 [査読有り][通常論文]
     
    1-mu m-thick Cu thin lines with adjacent connections, which simulate via structures in large-scale integration circuits, were fabricated on Si3N4 membranes by both electron-beam evaporation and a focused ion beam for coherent x-ray diffraction measurements. A direct current was applied to a Cu thin line to prepare an electromigration sample. In the scanning electron microscope image of the electromigration sample, a roughness of a few hundred nanometers was observed on the surface around the via structures. Coherent x-ray diffraction patterns of both the thin line and electromigration samples were measured using synchrotron x-rays at SPring-8. Characteristic diffraction patterns resulting from both the shape of the Cu thin lines and the defects around the via structures formed by the application of the current were observed. Copyright (C) 2008 John Wiley & Sons, Ltd.
  • S. Matsuyama, H. Mimura, K. Katagishi, H. Yumoto, S. Handa, M. Fujii, Y. Sano, M. Shimura, M. Yabashi, Y. Nishino, K. Tamasaku, T. Ishikawa, K. Yamauchi
    SURFACE AND INTERFACE ANALYSIS 40 6-7 1042 - 1045 2008年06月 [査読有り][通常論文]
     
    We have developed a scanning X-ray fluorescence microscope (SXFM) using Kirkpatrick-Baez mirror optics, which enables achromatic and highly efficient focusing, at BL29XUL of SPring-8. The SXFM enables observations of multielement distributions inside a sample with high resolution and high sensitivity. Previously, we have reported the high spatial resolution of a newly developed SXFM. In the present paper, we focus on the high sensitivity of the SXFM. By observations of fine test patterns using the X-ray beam probe having a size of 100 x 100 nm(2) and an energy of 15 keV, the lower detection limit for the visualization of elemental distributions was investigated. As a result, the lower detection limits were found to be 0.009 fg (gallium) and 0.012 fg (tungsten). Copyright (C) 2008 John Wiley & Sons, Ltd.
  • M. Mulazzi, A. Chainani, Y. Takata, Y. Tanaka, Y. Nishino, K. Tamasaku, T. Ishikawa, T. Takeuchi, Y. Ishida, Y. Senba, H. Ohashi, S. Shin
    PHYSICAL REVIEW B 77 22 224425  2008年06月 [査読有り][通常論文]
     
    We study the temperature dependence of the exchange stiffness A(T) of a thin FePd(001) film, which exhibits well-ordered magnetic stripe domains. We employed two different methods: (i) applying an exact micromagnetic model of the nucleation point and (ii) a detailed analysis of the temperature dependence of the saturation magnetization. The experimental data needed as input for the theoretical model are the stripe domain width and the nucleation field, and these were obtained as a function of temperature using soft x-ray magnetic scattering and superconducting quantum interference device (SQUID) magnetometry, respectively. The temperature independence of the domain width is very important from the point of view of the energetics of the FePd film, i.e., the number of magnetic domains remains constant per unit area. From this experimental finding we infer that the exchange stiffness must vary as a function of the temperature. We show that the A(T) dependence obtained with the two procedures are consistent but different from the phenomenological law A(T)proportional to M(S)(2)(T), normally assumed to be valid in the temperature range examined (T=50-250 K), an intermediate temperature range for which there is no known expression of the magnetization as a function of the temperature. We have also investigated the Fe 3s core level and valence band of FePd using hard x-ray photoemission spectroscopy. The Fe 3s spectra exhibit negligible changes in the temperature range investigated, while small changes occurring over large energy scales are observed in the valence-band spectra. Based on the lack of consistency of the magnetometry and scattering results compared to local-moment theories, these results favor an itinerant magnetism picture for FePd.
  • M. Taguchi, M. Matsunami, Y. Ishida, R. Eguchi, A. Chainani, Y. Takata, M. Yabashi, K. Tamasaku, Y. Nishino, T. Ishikawa, Y. Senba, H. Ohashi, S. Shin
    PHYSICAL REVIEW LETTERS 100 20 206401  2008年05月 [査読有り][通常論文]
     
    We have reexamined the valence-band (VB) and core-level electronic structure of NiO by means of hard and soft x-ray photoemission spectroscopies. The spectral weight of the lowest energy state was found to be enhanced in the bulk sensitive Ni 2p core-level spectrum. A configuration-interaction model including a bound state screening has shown agreement with the core-level spectrum and off- and on-resonance VB spectra. These results identify the lowest energy states in the core-level and VB spectra as the Zhang-Rice (ZR) doublet bound states, consistent with the spin-fermion model and recent ab initio calculations within dynamical mean-field theory. The results indicate that the ZR character first ionization (the lowest hole-addition) states are responsible for transport properties in NiO and doped NiO.
  • M. Matsunami, K. Horiba, M. Taguchi, K. Yamamoto, A. Chainani, Y. Takata, Y. Senba, H. Ohashi, M. Yabashi, K. Tamasaku, Y. Nishino, D. Miwa, T. Ishikawa, E. Ikenaga, K. Kobayashi, H. Sugawara, H. Sato, H. Harima, S. Shin
    PHYSICAL REVIEW B 77 16 165126  2008年04月 [査読有り][通常論文]
     
    Semiconducting skutterudite CeFe(4)P(12) is investigated by synchrotron x-ray photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). Ce 3d core-level PES and 3d-4f XAS, in combination with single-impurity Anderson model (SIAM) calculations, confirm features due to f(0), f(1), and f(2) configurations. The Ce 3d-4f resonant-PES spectra provide the Ce 4f density of states (DOS), which indicates the absence of a Kondo resonance at the Fermi level, but can still be explained by SIAM with a small gap in non-f DOS. While Ce 4f partial DOS from band structure calculations is consistent with the main Ce 4f DOS, the importance of SIAM for core-level PES and XAS spectra quantifies the mixed valence for semiconducting CeFe(4)P(12), derived from strong hybridization between non-f conduction and Ce 4f DOS.
  • Hiroki Wadati, Yasushi Hotta, Atsushi Fujimori, Tomofumi Susaki, Harold Y. Hwang, Yasutaka Takata, Koji Horiba, Masaharu Matsunami, Shik Shin, Makina Yabashi, Kenji Tamasaku, Yoshinori Nishino, Tetsuya Ishikawa
    PHYSICAL REVIEW B 77 4 45122  2008年01月 [査読有り][通常論文]
     
    We have studied the electronic structure of multilayers composed of a band insulator LaAlO(3) (LAO) and a Mott insulator LaVO(3) (LVO) by means of hard x-ray photoemission spectroscopy, which has a probing depth as large as similar to 60 A. The Mott-Hubbard gap of LVO remained open at the interface, indicating that the interface is insulating unlike the LaTiO(3)/SrTiO(3) multilayers. We found that the valence of V in LVO was partially converted from V(3+) to V(4+) only at the interface on the top side of the LVO layer and that the amount of V(4+) increased with LVO layer thickness. We suggest that the electronic reconstruction to eliminate the polarity catastrophe inherent in the polar heterostructure is the origin of the highly asymmetric valence change at the LAO/LVO interfaces.
  • Hidekazu Mimura, Hirokatsu Yumoto, Satoshi Matsuyama, Soichiro Handa, Takashi Kimura, Yasuhisa Sano, Makina Yabashi, Yoshinori Nishino, Kenji Tamasaku, Tetsuya Ishikawa, Kazuto Yamauchi
    PHYSICAL REVIEW A 77 1 15812  2008年01月 [査読有り][通常論文]
     
    We present a remarkably accurate method for determining the wave field of an x-ray nanobeam. The intensity profile of a beam was directly measured over a range of three orders of magnitude while its phase distribution was successfully recovered using an iterative algorithm. The evolution of the wave field along the beam propagation direction was precisely simulated, and there was good agreement with the experimental results.
  • Huaidong Jiang, Damien Ramunno-Johnson, Changyong Song, Bagrat Amirbekian, Yoshiki Kohmura, Yoshinori Nishino, Yukio Takahashi, Tetsuya Ishikawa, Jianwei Miao
    PHYSICAL REVIEW LETTERS 100 3 38103  2008年01月 [査読有り][通常論文]
     
    We for the first time applied x-ray diffraction microscopy to the imaging of mineral crystals inside biological composite materials-intramuscular fish bone-at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization. Based on the experimental results and biomineralization analyses, we suggested a dynamic model to account for the nucleation and growth of mineral crystals in the collagen matrix. The results obtained from this study not only further our understanding of the complex structure of bone, but also demonstrate that x-ray diffraction microscopy will become an important tool to study biological materials.
  • Takata, Y., Kayanuma, Y., Oshima, S., Tanaka, S., Yabashi, M., Tamasaku, K., Nishino, Y., Matsunami, M., Eguchi, R., Chainani, A., Oura, M., Takeuchi, T., Senba, Y., Ohashi, H., Shin, S., Ishikawa, T.
    Physical Review Letters 101 13 1 - 4 2008年 [査読有り][通常論文]
  • Hidekazu Mimura, Shinya Morita, Takashi Kimura, Daisuke Yamakawa, Weimin Lin, Yoshihiro Uehara, Hirokatsu Yumoto, Satoshi Matsuyama, Yoshinori Nishino, Kenji Tamasaku, Haruhiko Ohashi, Makina Yabashi, Tetsuya Ishikawa, Hitoshi Ohmori, Kazuto Yamauchi
    ADVANCES IN X-RAY/EUV OPTICS AND COMPONENTS III 7077 2008年 [査読有り][通常論文]
     
    We describe the fabrication of a long mirror for focusing X-ray free electron lasers to nanometer dimension, for the production of high photon density beams. The focusing mirror has an elliptical curved shape with a length of 400 mm and focal length of 550 mm. Electrolytic in-process dressing grinding is used for first-step figuring and elastic emission machining is employed for final figuring and surface smoothing. Figure accuracy with a peak-to-valley height of 2 nm is achieved. A focusing test was performed at BL29XUL of SPring-8 and found the focused beam size to be approximately 75 nm at 15 keV, very similar to the theoretical value.
  • Takashi Kimura, Soichiro Handa, Hidekazu Mimura, Hirokatsu Yumoto, Daisuke Yamakawa, Satoshi Matsuyama, Yasuhisa Sano, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    ADVANCES IN X-RAY/EUV OPTICS AND COMPONENTS III 7077 2008年 [査読有り][通常論文]
     
    We present the development of a phase compensator for wavefront control of X-rays. The optical device is a 150 mm-long total reflection mirror, the shape of which can be curved by adjusting the bias voltages of 36 piezoelectric ceramic plates attached to the mirror. The mirror surface was smoothed and made flat by elastic emission machining. To achieve a high degree of the accuracy in the controllability of a curved line, a Fizeau interferometer is placed in front of the mirror surface to monitor its shape in the experiment. We will apply this device to the optical system for the realization of sub-10-nm hard X-ray focusing.
  • Junichi Takaobushi, Mizue Ishikawa, Shigenori Ueda, Eiji Ikenaga, Jung-Jin Kim, Masaaki Kobata, Yukiharu Takeda, Yuji Saitoh, Makina Yabashi, Yoshinori Nishino, Daigo Miwa, Kenji Tamasaku, Tetsuya Ishikawa, Issei Satoh, Hidekazu Tanaka, Keisuke Kobayashi, Tomoji Kawai
    PHYSICAL REVIEW B 76 20 205108  2007年11月 [査読有り][通常論文]
     
    We fabricated Fe(3-x)M(x)O(4) (M=Mn,Zn) thin film by pulsed laser deposition technique and investigated their electronic structure by hard x-ray photoemission spectroscopy (HX-PES) and x-ray magnetic circular dichroism (XMCD). HX-PES and XMCD revealed that the solid solution system of Fe(3-x)M(x)O(4) (M=Mn,Zn) is the best candidate for tunable ferromagnetic oxide semiconductor judging from systematic change of Fe, Mn core-level spectra, and valence band spectra by substitution. We present a model to explain modulation of electric and magnetic properties and electronic structure evolution caused by strongly correlated electron.
  • M. Taguchi, A. Chainani, N. Kamakura, K. Horiba, Y. Takata, M. Yabashi, K. Tamasaku, Y. Nishino, D. Miwa, T. Ishikawa, S. Shin, E. Ikenaga, T. Yokoya, K. Kobayashi, T. Mochiku, K. Hirata, K. Motoya
    PHYSICAL REVIEW B 76 16 169901  2007年10月 [査読有り][通常論文]
  • Toyohiko Kinoshita, Eiji Ikenaga, Jungjin Kim, Shigenori Ueda, Masaaki Kobata, James R. Harries, Kenya Shimada, Akihiro Ino, Kenji Tamasaku, Yoshinori Nishino, Tetsuya Ishikawa, Keisuke Kobayashi, Wolfgang Drube, Christof Kunz
    SURFACE SCIENCE 601 20 4754 - 4757 2007年10月 [査読有り][通常論文]
     
    We analyze the excitation of secondary electrons by hard-X-rays in subsurface layers. By studying core-excited photoelectron lines and their plasmon satellites in photoemission spectra, we show how electrons excited by hard-X-rays can carry information from deep regions deep within the sample to the surface. It is believed that the decay of high-energy photoelectrons via plasmon-loss is strongly related to the production of secondary electrons. For high-energy electrons, however, the momentum transfer to plasmons is small compared to the electron's initial momentum, so the lateral position on the surface from which the secondary electrons are emitted is close to that of the atom initially excited by the hard-X-rays. This explains why the spatial resolution of hard-X-ray photoelectron emission microscope (HX-PEEM) images is good even if the buried interface is covered by a film with a thickness many times the inelastic mean free path of the primary electrons. This argument explains well recent HX-PEEM results. (c) 2007 Elsevier B.V. All rights reserved.
  • Toyohiko Kinoshita, Eiji Ikenaga, Jungjin Kim, Shigenori Ueda, Masaaki Kobata, James R. Harries, Kenya Shimada, Akihiro Ino, Kenji Tamasaku, Yoshinori Nishino, Tetsuya Ishikawa, Keisuke Kobayashi, Wolfgang Drube, Christof Kunz
    SURFACE SCIENCE 601 20 4754 - 4757 2007年10月 [査読有り][通常論文]
     
    We analyze the excitation of secondary electrons by hard-X-rays in subsurface layers. By studying core-excited photoelectron lines and their plasmon satellites in photoemission spectra, we show how electrons excited by hard-X-rays can carry information from deep regions deep within the sample to the surface. It is believed that the decay of high-energy photoelectrons via plasmon-loss is strongly related to the production of secondary electrons. For high-energy electrons, however, the momentum transfer to plasmons is small compared to the electron's initial momentum, so the lateral position on the surface from which the secondary electrons are emitted is close to that of the atom initially excited by the hard-X-rays. This explains why the spatial resolution of hard-X-ray photoelectron emission microscope (HX-PEEM) images is good even if the buried interface is covered by a film with a thickness many times the inelastic mean free path of the primary electrons. This argument explains well recent HX-PEEM results. (c) 2007 Elsevier B.V. All rights reserved.
  • Yukio Takahashi, Yoshinori Nishino, Tetsuya Ishikawa
    PHYSICAL REVIEW A 76 3 33822  2007年09月 [査読有り][通常論文]
     
    Coherent x-ray diffraction microscopy (CXDM) using an x-ray free electron laser (XFEL) is expected to open up a new frontier of structural studies in materials science and biology, while radiation damage of samples under the extremely intense x rays is a matter of considerable concern. Two superresolution methods for CXDM proposed in this paper offer solutions of the problems by numerical data analysis. Promising results for future applications of CXDM with XFEL were obtained in a numerical simulation.
  • Takata, Y, Kayanuma, Y, Yabashi, M, Tamasaku, K, Nishino, Y, Miwa, D, Harada, Y, Horiba, K, Shin, S, Tanaka, S, Ikenaga, E, Kobayashi, K, Senba, Y, Ohashi, H, Ishikawa, T
    Physical Review B 75 23 233404  2007年06月 [査読有り][通常論文]
  • Y. Takata, Y. Kayanuma, M. Yabashi, K. Tamasaku, Y. Nishino, D. Miwa, Y. Harada, K. Horiba, S. Shin, S. Tanaka, E. Ikenaga, K. Kobayashi, Y. Senba, H. Ohashi, T. Ishikawa
    PHYSICAL REVIEW B 75 23 2007年06月 [査読有り][通常論文]
     
    High-energy-resolution C 1s photoelectron spectra of graphite were measured at excitation energies of 340, 870, 5950, and 7940 eV using synchrotron radiation. On increasing the excitation energy, i.e., increasing kinetic energy of the photoelectron, the bulk origin C 1s peak position shifts to higher binding energies. This systematic shift is due to the kinetic-energy loss of the high-energy photoelectron by kicking the atom and is clear evidence of the recoil effect in photoelectron emission. It is also observed that the asymmetric broadening increases for the higher-energy photoelectrons. All these recoil effects can be quantified in the same manner as the Mossbauer effect for gamma-ray emission from nuclei embedded in crystals.
  • Y. Takahashi, Y. Nishino, T. Ishikawa, E. Matsubara
    Journal of Physics: Conference Series 83 1 2007年06月01日 [査読有り][通常論文]
     
    A coherent x-ray diffraction pattern of a Sn-Zn eutectic alloy particle prepared by a gas-atomized method was measured. Noncentrosymmetric speckle patterns resulting from submicron-sized Zn- and Sn-rich regions in the Sn-Zn alloy were observed. © 2007 IOP Publishing Ltd.
  • Andrei Y. Nikulin, Ruben A. Dilanian, Nadia A. Zatsepin, Brian M. Gable, Barry C. Muddle, Alexei Y. Souvorov, Yoshinori Nishino, Tetsuya Ishikawa
    NANO LETTERS 7 5 1246 - 1250 2007年05月 [査読有り][通常論文]
     
    A novel approach to X-ray diffraction data analysis for nondestructive determination of the shape of nanoscale particles and clusters in three-dimensions is illustrated with representative examples of composite nanostructures. The technique is insensitive to the X-ray coherence, which allows 3-D reconstruction of a modal image without tomographic synthesis and in situ analysis of large (over a several cubic millimeters) volume of material with a spatial resolution of few nanometers, rendering the approach suitable for laboratory facilities.
  • Electronic structure of 3d(1) configuration vanadium oxides studied by soft X-ray and hard X-ray photoemission spectroscopy
    Eguchi, R, Taguchi, M, Horiba, K, Matsunami, M, Yamamoto, K, Takata, Y, Chainani, A, Yabashi, M, Miwa, D, Nishino, Y, Tamasaku, K, Ishikawa, T, Senba, Y, Ohashi, H, Inoue, I. H, Muraoka, Y, Hiroi, Z, Shin, S
    Journal of Electron Spectroscopy And Related Phenomena 156 XCVII - XCVIII 2007年05月 [査読有り][通常論文]
  • Electronic structure of ferromagnetic semiconductor Ge1-xMnxTe investigated by hard X-ray photoemission spectroscopy
    Senba, S, Fukuma, Y, Sato, H, Goto, K, Asada, H, Koyanagi, T, Taniguchi, M, Ikenaga, E, Kim, J. J, Ueda, S, Kobata, M, Miwa, D, Nishino, Y, Tamasaku, K, Ishikawa, T, Kobayashi, K
    Journal of Electron Spectroscopy And Related Phenomena 156 LXXXIX - LXXXIX 2007年05月 [査読有り][通常論文]
  • E. Ikenaga, M. Kobata, J. J. Kim, A. Wakabayashi, Y. Nishino, K. Tamasaku, Y. Sakane, T. Ishikawa, S. Komiya, K. Kobayashi
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 156 336 - 339 2007年05月 [査読有り][通常論文]
     
    The adsorption states for lubricant molecules have been investigated using hard X-ray (hv = 7.95 keV) photoemission spectroscopy (HX-PES). This method has the advantage for the organic molecules to be able to measure damage few. Being aware of the fact that P atoms exist only in cyclotriphosphazene base, we measured the take-off angle dependence of the P1s spectra. Each spectrum consists from two peaks, that is, substrate NiP peak and cyclotriphosphazene P peak. The cyclotriphosphazene P peak rapidly disappears with increasing take-off angle. We have also measured C1s spectra. Combining these experimental results, we have found that the adsorption state of cyclotriphosphazene end group is undergoing. (c) 2007 Elsevier B.V. All rights reserved.
  • R. Eguchi, M. Taguchi, M. Matsunami, K. Horiba, K. Yamamoto, A. Chainani, Y. Takata, M. Yabashi, D. Miwa, Y. Nishino, K. Tamasaku, T. Ishikawa, Y. Senba, H. Ohashi, I. H. Inoue, Y. Muraoka, Z. Hiroi, S. Shin
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 156 421 - 425 2007年05月 [査読有り][通常論文]
     
    We investigate the electronic structure of 3d(1) configuration vanadium oxides (VO2, SrVO3 and CaVO3) using soft X-ray (SX) and hard X-ray (HX) photoemission spectroscopy (PES). The valence band spectra of VO2 in SX- and HX-PES clearly show the opening of a gap at E-F across the metal-insulator transition. Spectral changes in the V 2p and O 1s core levels were also observed. In addition, 3d(1) configuration correlated metals SrVO3 and CaVO3 are typical materials whose valence band spectra are compared with dynamical mean-field theory. The V 2p and V 1s core level HX-PES of SrVO3 and CaVO3 show clear additional well-screened features. These features originate from bulk screening by a coherent band at EF. These spectra are nicely reproduced by a cluster model calculation, indicating a difference of the parameter V* for the interaction strength between the central V 3d orbitals and the coherent band. (c) 2007 Elsevier B.V. All rights reserved.
  • Yukio Takahashi, Yoshinori Nishino, Tetsuya Ishikawa, Eiichiro Matsubara
    APPLIED PHYSICS LETTERS 90 18 184105  2007年04月 [査読有り][通常論文]
     
    An approach for evaluating three-dimensional spatial distribution of precipitates buried within a bulk alloy by coherent x-ray diffraction microscopy (CXDM) is proposed. In this study, the outer shape and the internal structure of the micrometer-sized sample in a precipitation-hardened aluminum alloy are observed by CXDM. A high-electron-density region resulting from precipitates is clearly visualized, implying that the precipitates distribute inhomogeneously in the Al matrix at several tens of nanometer scale. This is the important result toward in situ observation of the formation of internal structures in metallic materials on the nanomesoscale by CXDM with x-ray free electron lasers. (c) 2007 American Institute of Physics.
  • K. Shimada, M. Higashiguchi, M. Arita, H. Namatame, M. Taniguchi, S.-i. Fujimori, Y. Saitoh, A. Fujimori, Y. Takata, S. Shin, K. Kobayashi, E. Ikenaga, M. Yabashi, K. Tamasaku, Y. Nishino, D. Miwa, T. Ishikawa, T. Sasakawa, T. Takabatake
    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 310 2 E57 - E58 2007年03月 [査読有り][通常論文]
     
    We have examined the electronic states of the Kondo semiconductor CeRhAs and the semimetal CeRhSb by means of high- resolution photoemission spectroscopy using tunable photon energies from hv = 40 up to 5948 eV. On the basis of the photon- energy dependence of the photoionization cross- section, we have elucidated the p - d - f hybridized states in these compounds. (c) 2006 Elsevier B. V. All rights reserved.
  • R. Eguchi, Y. Takata, M. Matsunami, K. Horiba, K. Yamamoto, M. Taguchi, A. Chainani, M. Yabashi, D. Miwa, Y. Nishino, K. Tamasaku, T. Ishikawa, Y. Senba, H. Ohashi, I. H. Inoue, S. Shin
    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 310 2 E289 - E291 2007年03月 [査読有り][通常論文]
     
    We study the electronic structure of Mott-Hubbard systems SrVO3 and CaVO3 with photoemission spectroscopy (PES) using hard Xrays (HX) (hv similar to 8 keV) and soft X-rays (SX) (hv similar to 900 eV). In HX-PES results, the V 2p core levels of SrVO3 and CaVO3 show clear additional intensity, which are not observed in SX-PES. These features originate from bulk screening by coherent states at Fermi level as observed in other 3d transition metal oxides. From the comparison between SrVO3 and CaVO3 in HX-PES, the intensity in SrVO3 is nearly similar to CaVO3. The results suggest screening from coherent states is more efficient in HX-PES compared to SX-PES. (c) 2006 Elsevier B.V. All rights reserved.
  • Changyong Song, Damien Ramunno-Johnson, Yoshinori Nishino, Yoshiki Kohmura, Tetsuya Ishikawa, Chien-Chun Chen, Ting-Kuo Lee, Jianwei Miao
    PHYSICAL REVIEW B 75 1 12102  2007年01月 [査読有り][通常論文]
     
    We have shown that, when the linear oversampling ratio >= 2, exactly oversampled diffraction patterns can be directly obtained from measured data through deconvolution. By using computer simulations and experimental data, we have demonstrated that exact oversampling of diffraction patterns distinctively improves the quality of phase retrieval. Furthermore, phase retrieval based on the exact sampling scheme is independent of the oversampling ratio, which can significantly reduce the radiation dosage to the samples. We believe that the present work will contribute to high-quality image reconstruction of materials science samples and biological structures using x-ray diffraction microscopy.
  • Hidekazu Mimura, Hirokatsu Yumoto, Satoshi Matsuyama, Yasuhisa Sano, Kazuya Yamamura, Yuzo Mori, Makina Yabashi, Yoshinori Nishino, Kenji Tamasaku, Tetsuya Ishikawa, Kazuto Yamauchi
    APPLIED PHYSICS LETTERS 90 5 51903  2007年01月 [査読有り][通常論文]
     
    Nanofocused x rays are indispensable because they can provide high spatial resolution and high sensitivity for x-ray nanoscopy/spectroscopy. A focusing system using total reflection mirrors is one of the most promising methods for producing nanofocused x rays due to its high efficiency and energy-tunable focusing. The authors have developed a fabrication system for hard x-ray mirrors by developing elastic emission machining, microstitching interferometry, and relative angle determinable stitching interferometry. By using an ultraprecisely figured mirror, they realized hard x-ray line focusing with a beam width of 25 nm at 15 keV. The focusing test was performed at the 1-km-long beamline of SPring-8. (c) 2007 American Institute of Physics.
  • H. Mimura, S. Matsuyama, H. Yumoto, S. Handa, T. Kimura, Y. Sano, K. Tamasaku, Y. Nishino, M. Yabashi, T. Ishikawa, K. Yamauchi
    ADVANCES IN X-RAY/EUV OPTICS AND COMPONENTS II 6705 2007年 [査読有り][通常論文]
     
    Nanofocused X-rays are indispensable because they can provide high spatial resolution and high sensitivity for X-ray nanoscopy/spectroscopy. A focusing system with reflective optics is one of the most promising methods for producing nanofocused X-rays due to its high efficiency and beams size. So, far we realize efficient hard X-ray focusing with a beam size of 25nm. Our next project is realization of sub-10nm hard X-ray focusing. Here, we describe the design of the graded multilayer mirror and evaluation method for hard X-ray focused beam.
  • J. J. Kim, E. Ikenaga, M. Kobata, M. Yabashi, K. Kobayashi, Y. Nishino, D. Miwa, K. Tamasaku, T. Ishikawa
    SYNCHROTRON RADIATION INSTRUMENTATION, PTS 1 AND 2 879 1407 - + 2007年 [査読有り][通常論文]
     
    Hard X-ray photoemission spectroscopy has been shown to be a powerful tool for investigating the bulk sensitive chemical and electronic states of solid materials. Mgh energy resolution and high throughput have been achieved using the highly brilliant undulator X-rays available at SPring-8 along with an electron analyzer optimized for high electron kinetic energy. Here, we report the performance and characteristics of hard X-ray photoemission spectroscopy of photoelectron excitation energies of up to 10 keV.
  • M. Kobata, E. Ikenaga, J. J. Kim, M. Yabashi, K. Kobayashi, D. Miwa, Y. Nishino, K. Tamasaku, T. Ishikawa, C. G. Jin, Y. Sasaki, K. Okashita, H. Tamura, H. Ito, B. Mizuno, T. Okumura
    PHYSICS OF SEMICONDUCTORS, PTS A AND B 893 1491 - + 2007年 [査読有り][通常論文]
     
    Recently, we have shown that hard X-ray photoemission spectroscopy (HX-PES) using undulator X-rays at SPring-8 is quite feasible with both high resolution and high throughput. Here we report an application of HX-PES to the characterization of electronic and chemical states of ultra shallow plasma doped samples. We found that the shift in chemical binding energy by impurity activation can be measured with high accuracy. The binding energy of Si Is changes according to the shift in Fermi level as the carrier concentration varies. Thus, the active carrier concentration of ultra-shallow junction region can be measured by non-destructive HX-PES with high accuracy.
  • Soichiro Handa, Hidekazu Mimura, Satoshi Matsuyama, Hirokatsu Yumoto, Takashi Kimura, Yasuhisa Sano, Kenji Tamasaku, Yoshinori Nishino, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    ADVANCES IN METROLOGY FOR X-RAY AND EUV OPTICS II 6704 2007年 [査読有り][通常論文]
     
    Extremely high surface figure accuracy is required for hard x-ray nanofocusing mirrors to realize an ideal spherical wavefront in a reflected x-ray beam. We performed the figure correction of an elliptically figured mirror by a differential deposition technique on the basis of the wavefront phase error, which was calculated by a phase-retrieval method using only intensity profile on the focal plane. The measurements of the intensity profiles were performed at the 1-km-long beamline at SPring-8. The two measurements before and after the figure correction indicate that the beamwaist structure around the focal point is greatly improved.
  • IKENAGA E, KIM JJ, KOBATA M
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 156 LXXXIII  2007年 [査読有り][通常論文]
  • SENBA S, FUKUMA Y, SATO H
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 156 LXXXIX  2007年 [査読有り][通常論文]
  • Junichi Takaobushi, Hidekazu Tanaka, Tomoji Kawai, Shigenori Ueda, Jung-Jin Kim, Masaaki Kobata, Eiji Ikenaga, Makina Yabashi, Keisuke Kobayashi, Yoshinori Nishino, Daigo Miwa, Kenji Tamasaku, Tetsuya Ishikawa
    APPLIED PHYSICS LETTERS 89 24 242507  2006年12月 [査読有り][通常論文]
     
    Epitaxial ferri(ferro)magnetic Fe3-xZnxO4 thin films (x=0-0.9) were prepared using a pulsed-laser deposition technique. The electrical conductivity and magnetic properties of Fe3-xZnxO4 thin film were systematically modulated for the entire range of Zn substitution. Anomalous Hall coefficient measurements revealed the presence of spin-polarized carriers at room temperature. Valence band spectra obtained by hard x-ray photoemission spectroscopy revealed that the density of states near the Fermi level was reduced with an increasing Zn concentration of x. These results indicate that this system will serve as a tunable ferromagnetic semiconductor with a strong electron correlation. (c) 2006 American Institute of Physics.
  • Y. Taguchi, K. Yamamoto, K. Mimura, K. Ichikawa, K. Kitamoto, O. Aita, H. Ishibashi, Y. Takata, K. Horiba, S. Shin, M. Yabashi, K. Tamasaku, Y. Nishino, D. Miwa, T. Ishikawa, E. Ikenaga, K. Kobayashi
    RADIATION PHYSICS AND CHEMISTRY 75 11 2072 - 2075 2006年11月 [査読有り][通常論文]
     
    We have measured Ir 4f core-level photoemission spectra using an excitation photon energy of 6 keV for single crystalline CuIr2S4 at 250 and 200 K across the metal-insulator transition temperature of about 226 K. The Ir 417 spin-orbit doublet shifts by about 0.25eV towards higher binding energy with decreasing temperature. Tails and satellites around 1 and 13 eV, respectively, higher in binding energy than the peaks of Ir 4f doublets are observed in the 250-K spectrum, but they almost disappear at 200 K. The peak analysis here done indicates that the Ir 4f spectrum at 200 K consists of two components 0.2 eV apart corresponding to the charge separation of Ir ions in CuIr2S4. (c) 2006 Elsevier Ltd. All rights reserved.
  • Jianwei Miao, Chien-Chun Chen, Changyong Song, Yoshinori Nishino, Yoshiki Kohmura, Tetsuya Ishikawa, Damien Ramunno-Johnson, Ting-Kuo Lee, Subhash H. Risbud
    PHYSICAL REVIEW LETTERS 97 21 215503  2006年11月 [査読有り][通常論文]
     
    In combination of direct phase retrieval of coherent x-ray diffraction patterns with a novel tomographic reconstruction algorithm, we, for the first time, carried out quantitative 3D imaging of a heat-treated GaN particle with each voxel corresponding to 17x17x17 nm(3). We observed the platelet structure of GaN and the formation of small islands on the surface of the platelets, and successfully captured the internal GaN-Ga2O3 core shell structure in three dimensions. This work opens the door for nondestructive and quantitative imaging of 3D morphology and 3D internal structure of a wide range of materials at the nanometer scale resolution that are amorphous or possess only short-range atomic organization.
  • S. Matsuyama, H. Mimura, H. Yumoto, Y. Sano, K. Yamamura, M. Yabashi, Y. Nishino, K. Tamasaku, T. Ishikawa, K. Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 77 10 103102  2006年10月 [査読有り][通常論文]
     
    We developed a high-spatial-resolution scanning x-ray fluorescence microscope (SXFM) using Kirkpatrick-Baez mirrors. As a result of two-dimensional focusing tests at BL29XUL of SPring-8, the full width at half maximum of the focused beam was achieved to be 50 x 30 nm(2) (VxH) under the best focusing conditions. The measured beam profiles were in good agreement with simulated results. Moreover, beam size was controllable within the wide range of 30 - 1400 nm by changing the virtual source size, although photon flux and size were in a trade-off relationship. To demonstrate SXFM performance, a fine test chart fabricated using focused ion beam system was observed to determine the best spatial resolution. The element distribution inside a logo mark of SPring-8 in the test chart, which has a minimum linewidth of approximately 50 - 60 nm, was visualized with a spatial resolution better than 30 nm using the smallest focused x-ray beam. (c) 2006 American Institute of Physics.
  • Eiko Hashimoto, Anton Maksimenko, Hiroshi Sugiyama, Kazuyuki Hyodo, Daisuke Shimao, Yoshinori Nishino, Tetsuya Ishikawa, Masami Ando
    ZOOLOGICAL SCIENCE 23 9 809 - 813 2006年09月 [査読有り][通常論文]
     
    We have developed X-ray refraction-based computed tomography (CT) that is able to visualize soft tissue in between hard tissue. The experimental system consists of Si(220) diffraction double-crystals and is called the DEI (diffraction-enhanced imaging) method, in which the object is located between the crystals and a CCD camera to acquire data as 360 X-ray images. The X-ray energy used was 17.5 keV. The algorithm used to reconstruct CT images was developed by A. Malksimenko and colleagues. We successfully visualized articular cartilage and the distribution of bone marrow, which are inner structures. Our method has much higher contrast compared to the conventional absorption-based CT system.
  • S. Matsuyama, H. Mimura, H. Yumoto, H. Hara, K. Yamamura, Y. Sano, K. Endo, Y. Mori, M. Yabashi, Y. Nishino, K. Tamasaku, T. Ishikawa, K. Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 77 9 93107  2006年09月 [査読有り][通常論文]
     
    X-ray focusing using Kirkpatrick-Baez (KB) mirrors is promising owing to their capability of highly efficient and energy-tunable focusing. We report the development of a mirror manipulator which enables KB mirror alignment with a high degree of accuracy. Mirror alignment tolerances were estimated using two types of simulators. On the basis of the simulation results, the mirror manipulator was developed to achieve an optimum KB mirror setup. As a result of focusing tests at BL29XUL of SPring-8, the beam size of 48x36 nm(2) (VxH) was achieved in the full width at half maximum at an x-ray energy of 15 keV. Spatial resolution tests showed that a scanning x-ray microscope equipped with the KB focusing system could resolve line-and-space patterns of 80 nm linewidth in a high visibility of 60%. (c) 2006 American Institute of Physics.
  • M. Sawada, A. Kimura, K. Miyoshi, J. Takeuchi, M. Arita, K. Shimada, H. Namatame, M. Taniguchi, T. Ishikawa, K. Tamasaku, Y. Nishino, D. Miwa, Y. Takata, S. Shin, K. Kobayashi, E. Ikenaga, M. Yabashi, M. Awaji, A. Takeuchi
    PHYSICA B-CONDENSED MATTER 383 1 152 - 154 2006年08月 [査読有り][通常論文]
     
    We have carried out hard X-ray photoemission spectroscopy (HXPES) for pyrochlore molybdenum oxides Sm2Mo2O7 and Tb2Mo2O7 single crystals with excitation energy of 5.95 keV, in order to investigate electronic structures and correlations in the bulk. The Mo 3d core spectra show complex features, in contrast to an ordinary doublet spectral feature derived from the spin-orbit interaction, indicating significant electron correlation in the valence band. While an intense peak structure at similar to 0.5eV is observed in the valence band of Sm2Mo2O7, the peak is broadened and shifted way in Tb2Mo2O7, which suggests the difference of the electron correlation energy depending on the rare-earth site. (c) 2006 Elsevier B.V. All rights reserved.
  • Fabrication of ultraprecisely figured mirror for nano focusing hard-x-ray
    Hirokatsu Yumoto, Hidekazu Mimura, Satoshi Matsuyama, Souichiro Handa, Kazuya Yamamura, Yasuhisa Sano, Katsuyoshi Endo, Yuzo Mori, Makina Yabashi, Yoshinori Nishino, Kenji Tamasaku, Tetsuya Ishikawa, Kazuto Yamauchi
    Towards Synthesis of Micro-/Nano-systems 2006年08月 [査読有り][通常論文]
  • Hirokatsu Yumoto, Hidekazu Mimura, Satoshi Matsuyama, Soichiro Handa, Yasuhisa Sano, Makina Yabashi, Yoshinori Nishino, Kenji Tamasaku, Tetsuya Ishikawa, Kazuto Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 77 6 63712  2006年06月 [査読有り][通常論文]
     
    We have developed an at-wavelength wave-front metrology of a grazing-incidence focusing optical systems in the hard x-ray region. The metrology is based on numerical retrieval from the intensity profile around the focal point. We demonstrated the at-wavelength metrology and estimated the surface figure error on a test mirror. An experiment for measuring the focusing intensity profile was performed at the 1-km-long beamline (BL29XUL) of SPring-8. The obtained results were compared with the profile measured using an optical interferometer and were confirmed to be in good agreement with it. This technique is a potential method of characterizing wave-front aberrations on elliptical mirrors for sub-10-nm focusing. (c) 2006 American Institute of Physics.
  • AV Darahanau, AY Nikulin, RA Dilanian, BC Muddle, A Souvorov, Y Nishino, T Ishikawa
    APPLIED PHYSICS LETTERS 88 26 263113  2006年06月 [査読有り][通常論文]
     
    High-angular-resolution Fraunhofer diffraction data were collected from several samples with interfaces between dissimilar metals using synchrotron x-radiation. The refractive index profile in the vicinity of the interface of each sample was reconstructed with spatial resolution of about 80 nm by the phase retrieval x-ray diffractometry technique, using only limited a priori knowledge of the sample. These studies have demonstrated the viability of the technique as a nondestructive method of characterization of internal interfaces within multiphase materials. (c) 2006 American Institute of Physics.
  • K. Horiba, M. Taguchi, A. Chainani, Y. Takata, N. Kamakura, S. Shin, M. Yabashi, K. Tamasaku, Y. Nishino, D. Miwa, T. Ishikawa, E. Ikenaga, M. Awaji, A. Takeuchi, K. Kobayashi
    PHYSICA B-CONDENSED MATTER 378-80 1152 - 1153 2006年05月 [査読有り][通常論文]
     
    In order to clarify the intrinsic bulk electronic structure of strongly-correlated electron systems, we have realized hard X-ray photoemission spectroscopy with high energy-resolution at BL29XUL in SPring-8. The total energy resolution of 75 meV was achieved at the excitation energy of 5.95 keV. Large probing depth of about 100 angstrom enables us to probe intrinsic bulk electronic structure free from surface condition. The importance and capability of this technique are demonstrated by the drastic difference in the Cu 2p core-level spectra of Nd1.85Ce0.15CuO4 crystals obtained using soft and hard X-rays. (c) 2006 Elsevier B.V. All rights reserved.
  • JP Sutter, AQR Baron, D Miwa, Y Nishino, K Tamasaku, T Ishikawa
    JOURNAL OF SYNCHROTRON RADIATION 13 3 278 - 280 2006年05月 [査読有り][通常論文]
     
    The perfection of two commercial top-grade quartz crystal wafers has been investigated using Bragg reflection at theta(B) = 89.77 degrees of a 2.0 meV bandwidth beam of 9.979 keV X-rays by the (7 (4) over bar(3) over bar4) lattice planes. Topographic images show small defect concentrations (<= 5 cm(-2)). Energy scan widths are below 3 meV over 8 mm x 8 mm areas and 4 meV over the whole wafer (similar to 11 cm(2)). This suggests that quartz can be a useful optical material.
  • J. J. Kim, E. Ikenaga, M. Kobata, A. Takeuchi, M. Awaji, H. Makino, P. P. Chen, A. Yamamoto, T. Matsuoka, D. Miwa, Y. Nishino, T. Yamamoto, T. Yao, K. Kobayashi
    APPLIED SURFACE SCIENCE 252 15 5602 - 5606 2006年05月 [査読有り][通常論文]
     
    Recently, we have shown that hard X-ray photoemission spectroscopy using undulator X-rays at SPring-8 is quite feasible with both high resolution and high throughput. Here we report an application of hard X-ray photoemission spectroscopy to the characterization of electronic and chemical states of thin solid films, for which conventional PES is not applicable. As a typical example, we focus on the problem of the scatter in the reported band-gap values for InN. We show that oxygen incorporation into the InN film strongly modifies the valence and plays a crucial role in the band gap problem. The present results demonstrate the powerful applicability of high resolution photoemission spectroscopy with hard X-rays from a synchrotron source. (c) 2005 Elsevier B.V. All rights reserved.
  • JW Miao, Y Nishino, Y Kohmura, B Johnson, CY Song, SH Risbud, T Ishikawa
    PHYSICAL REVIEW LETTERS 96 11 119902  2006年03月 [査読有り][通常論文]
  • Hidekazu Tanaka, Yasutaka Takata, Koji Horiba, Munetaka Taguchi, Ashish Chainani, Shik Shin, Daigo Miwa, Kenji Tamasaku, Yoshinori Nishino, Tetsuya Ishikawa, Eiji Ikenaga, Mitsuhiro Awaji, Akihisa Takeuchi, Tomoji Kawai, Keisuke Kobayashi
    Physical Review B - Condensed Matter and Materials Physics 73 9 94403  2006年 [査読有り][通常論文]
     
    We report the bulk sensitive hard x-ray (hν=5.95 keV) core level photoemission spectroscopy to investigate the intrinsic electronic structure of strained (La0.85 Ba0.15) Mn O3 thin films. In a 20 nm thick well-strained film with strongly enhanced ferromagnetism, a new sharp satellite peak appeared at the low energy site of the Mn 2 p3 2 main peak whereas, a broader signal was observed for the unstrained film with 300 nm thickness. Cluster calculations revealed that the intensity corresponded to the density of the state at the Fermi level relating to the magnitude of the ferromagnetic order. The satellite intensity also agreed quantitatively with the square of the magnetization. © 2006 The American Physical Society.
  • Satoshi Matsuyama, Hidekazu Mimura, Mari Shimura, Hirokatsu Yumoto, Keiko Katagishi, Soichiro Handa, Akihiko Shibatani, Yasuhis Sano, Kazuya Yamamura, Yoshinori Nishino, Kenji Tamasaku, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchi
    ADVANCES IN X-RAY/EUV OPTICS, COMPONENTS, AND APPLICATIONS 6317 2006年 [査読有り][通常論文]
     
    We developed a high-spatial-resolution scanning X-ray fluorescence microscope (SXFM) with Kirkpatrick-Baez mirrors. As a result of focusing tests at 15 keV, the focused beam having a FWHM of 30 x 50 nm(2) was achieved. Additionally, the size was controllable within the wide range of 30 similar to 1400 nm merely by adjusting the X-ray source size. The observation of a fine test chart suggests that SXFM enables us to visualize the element distribution inside the pattern at a spatial resolution better than 30 run. We applied the SXFM to observe intracellular elemental distributions at a single-cell level, so that we could acquire element distribution maps with a spatial resolution of sub-100 nm and lower detection limit of 0.01 fg.
  • H. Mimura, S. Matsuyama, H. Yumoto, S. Handa, A. Shibatani, K. Katagishi, Y. Sano, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Yamauchi
    ADVANCES IN X-RAY/EUV OPTICS, COMPONENTS, AND APPLICATIONS 6317 2006年 [査読有り][通常論文]
     
    Focusing methods using mirror optics are intensively studied in the field of X-ray microscopy because mirror optics has useful features such as high photon efficiency and no chromatic aberrations. Employing a wave-optical method, we investigated the relationship between the nature of figure errors on the mirror surface and optics performances. We also evaluated glancing angle sensitivity to focused beam and beamwaist stuructures. Obtained results showed unprecedented degrees of surface figure accuracy such as higher than 4 nm was required to realize nearly diffraction limited nanobeam. This simulation can also give important information for align KB mirrors setup. Keyword: coherent X-ray, hard X-ray focusing, wave-optical simulation.
  • Y Kohmura, Y Nishino, T Ishikawa, JW Miao
    JOURNAL OF APPLIED PHYSICS 98 12 123105  2005年12月 [査読有り][通常論文]
     
    Coherent diffraction microscopy requires a well-defined illumination wave such as a plane wave on a specimen. Experimentally, a small pinhole or a focused beam is often used to reduce the illumination area but they unavoidably distort the waves. The distortion of the illumination wave causes artifacts in the phase retrieval of oversampled diffraction patterns. Using computer simulations, we searched for the conditions where strong artifacts arise by changing the Fresnel number, pinhole size, alignment error and photon statistics. The experimental setup with Fresnel number of around 1 and smaller than 1 realized a small reconstruction error when the pinhole radius is larger than a few times the specimen size. These conditions are suitable for the rotation of specimens for the three-dimensional (3D) observations. Such investigation will have an impact in the design of coherent diffraction microscopes for the 3D characterization of nanoscale materials and biological systems using the third generation synchrotron radiation and future x-ray free-electron lasers. (c) 2005 American Institute of Physics.
  • M Taguchi, A Chainani, K Horiba, Y Takata, M Yabashi, K Tamasaku, Y Nishino, D Miwa, T Ishikawa, T Takeuchi, K Yamamoto, M Matsunami, S Shin, T Yokoya, E Ikenaga, K Kobayashi, T Mochiku, K Hirata, J Hori, K Ishii, F Nakamura, T Suzuki
    PHYSICAL REVIEW LETTERS 95 17 177002  2005年10月 [査読有り][通常論文]
     
    Hard x-ray photoemission spectroscopy (PES) of Cu core electronic states, with a probing depth of similar to 60 angstrom, is used to show that the Zhang-Rice singlet feature is present in La2CuO4 but is absent in Nd2CuO4. Hole and electron doping in La2-xSrxCuO4 (LSCO) and Nd2-xCexCuO4 (NCCO) result in new well-screened features which are missing in soft x-ray PES. Impurity Anderson model calculations establish screening from doped states as its origin, which is strongly suppressed within 15 angstrom of the surface. Complemented with x-ray absorption spectroscopy, the small chemical-potential shift in core levels (similar to 0.2 eV) are shown to be consistent with modifications of valence and conduction band states spanning the band gap (similar to 1 eV) upon hole and electron doping in LSCO and NCCO.
  • S Matsuyama, H Mimura, H Yumoto, K Yamamura, Y Sano, K Endo, Y Mori, Y Nishino, K Tamasaku, T Ishikawa, M Yabashi, K Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 76 8 83114  2005年08月 [査読有り][通常論文]
     
    The spatial resolution of scanning x-ray microscopy depends on the beam size of focused x rays. Recently, nearly diffraction-limited line focusing has been achieved using elliptical mirror optics at the 100 nm level. To realize such focusing two-dimensionally in a Kirkpatrick-Baez system, the required accuracies of the mirror aligners in this system were estimated using optical simulators based on geometrical or wave-optical theories. A focusing unit fulfilling the required adjustment accuracies was constructed. The relationships between alignment errors and focused beam profiles were quantitatively examined at the 1 km long beamline (BL29XUL) of SPring-8 to be in good agreement with the simulation results. (c) 2005 American Institute of Physics.
  • JW Miao, Y Nishino, Y Kohmura, B Johnson, CY Song, SH Risbud, T Ishikawa
    PHYSICAL REVIEW LETTERS 95 8 85503  2005年08月 [査読有り][通常論文]
     
    The missing data problem, i.e., the intensities at the center of diffraction patterns cannot be experimentally measured, is currently a major limitation for wider applications of coherent diffraction microscopy. We report here that, when the missing data are confined within the centrospeckle, the missing data problem can be reliably solved. With an improved instrument, we recorded 27 oversampled diffraction patterns at various orientations from a GaN quantum dot nanoparticle and performed quantitative image reconstruction from the diffraction intensities alone. This work in principle clears the way for single-shot imaging experiments using x-ray free electron lasers.
  • AV Darahanau, AY Nikulin, A Souvorov, Y Nishino, BC Muddle, T Ishikawa
    OPTICS COMMUNICATIONS 251 1-3 100 - 108 2005年07月 [査読有り][通常論文]
     
    X-ray Fraunhofer diffraction data have been collected from a series of weakly thickness-modulated samples using a synchrotron source. Three different areas of a linear Fresnel zone structure etched in a silicon wafer each 10 mu m wide were studied. Each area studied included different numbers of zones, ranging from 6 to 20. An X-ray phase retrieval technique was used to profile the complex refractive index within the areas examined. The zone structure thickness profiles were mapped with a spatial resolution of 100 nm. (c) 2005 Elsevier B.V. All rights reserved.
  • A Chainani, T Yokoya, Y Takata, K Tamasaku, M Taguchi, T Shimojima, N Kamakura, K Horiba, S Tsuda, S Shin, D Miwa, Y Nishino, T Ishikawa, M Yabashi, K Kobayashi, H Namatame, M Taniguchi, K Takada, T Sasaki, H Sakurai, E Takayama-Muromachi
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 547 1 163 - 168 2005年07月 [査読有り][通常論文]
     
    We study the bulk electronic structure of Na(x)CoO(2 center dot)yH(2)O using Hard X-ray (HX, hv = 5.95KeV) synchrotron photoelectron spectroscopy (PES). The Co 2p core level spectra show well-separated Co3+ and Co4+ ions. Cluster calculations suggest low spin Co3+ and Co4+ character, and a moderate on-site Coulomb correlation energy U-dd similar to 3-5.5 eV. Photon-dependent valence band PES identifies Co 3d and 0 2p derived states, in near agreement with band structure calculations. We discuss the importance of HX-PES for studying correlated transition metal oxides. (c) 2005 Elsevier B.V. All rights reserved.
  • Y Takata, M Yabashi, K Tamasaku, Y Nishino, D Miwa, T Ishikawa, E Ikenaga, K Horiba, S Shin, M Arita, K Shimada, H Namatame, M Taniguchi, H Nohira, T Hattori, S Sodergren, B Wannberg, K Kobayashi
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 547 1 50 - 55 2005年07月 [査読有り][通常論文]
     
    We have realized hard X-ray (HX) photoelectron spectroscopy (PES) with high-throughput and high-energy-resolution for core level and valence band studies using high-energy and high-brilliance synchrotron radiation at BL29XU in SPring-8. Large escape depth of high-energy photoelectrons enables us to probe intrinsic bulk states almost free from surface condition. By use of a newly developed electron energy analyzer and well-focused X-rays, high-energy resolution of 75 meV (E/Delta E = 79, 000) was realized for 5.95 keV photoelectrons. (c) 2005 Elsevier B.V. All rights reserved.
  • H Yumoto, H Mimura, S Matsuyama, H Hara, K Yamamura, Y Sano, K Ueno, K Endo, Y Mori, M Yabashi, Y Nishino, K Tamasaku, T Ishikawa, K Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 76 6 63708  2005年06月 [査読有り][通常論文]
     
    In this study, we designed, fabricated, and evaluated a hard x-ray focusing mirror having an ideally focused beam with a full width at half maximum in the intensity profile of 36 nm at an x-ray energy of 15 keV. The designed elliptically curved shape was fabricated by a computer-controlled fabrication system using plasma chemical vaporization machining and elastic emission machining, on the basis of surface profiles accurately measured by combining microstitching interferometry with relative angle determinable stitching interferometry. A platinum-coated surface was employed for hard x-ray focusing with a large numerical aperture. Line-focusing tests on the fabricated elliptical mirror are carried out at the 1-km-long beamline of SPring-8. A full width at half maximum of 40 nm was achieved in the focused beam intensity profile under the best focus conditions. (c) 2005 American Institute of Physics.
  • Y Takata, K Tamasaku, Y Nishino, D Miwa, M Yabashi, E Ikenaga, K Horiba, M Arita, K Shimada, H Namatame, H Nohira, T Hattori, S Sodergren, B Wannberg, M Taniguchi, S Shin, T Ishikawa, K Kobayashi
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 144 1063 - 1065 2005年06月 [査読有り][通常論文]
     
    We have realized hard X-ray (HX) photoemission spectroscopy (PES) with high throughput and high-energy resolution for core level and valence band studies using high-energy and high-brilliance synchrotron radiation at SPring-8. This is a brand new method because large escape depth of high-energy photoelectrons enables us to probe intrinsic bulk states free from surface condition. By use of a newly developed electron energy analyzer and well-focused X-rays, high-energy resolution of 75 meV (E/Delta E = 79,000) was realized for 5.95 keV photoelectrons. (c) 2005 Elsevier B.V. All rights reserved.
  • N Kamakura, M Taguchi, K Yamamoto, K Horiba, A Chainani, Y Takata, E Ikenaga, H Namatame, M Taniguchi, M Awaji, A Takeuchi, K Tamasaku, Y Nishino, D Miwa, T Ishikawa, Y Ueda, K Kobayashi, S Shin
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 144 841 - 843 2005年06月 [査読有り][通常論文]
     
    We have studied vanadium oxides corresponding to formally 3d(0) (V2O5), 3d(1) (VO2), and 3d(2) (V2O3) configurations and compare them with mixed valent Na0.33V2O5, using hard X-ray core level photoemission spectroscopy (PES), which enables to probe bulk electronic states due to large escape depth of high kinetic energy photoelectrons. The quasi-one-dimensional mixed-valence compound Na0.33V2O5 and three-dimensional V2O3 undergo metal-insulator (MI) transition at T-MI = 135 and 160 K, respectively. The observed V 2p core level spectra of V2O5 and VO2 show a single peak with chemical shifts corresponding to the V5+ and V4+ while two components (V5+ and V4+) are observed in Na0.33V2O5. Metallic V2O3 shows a bulk character additional peak at low binding energy in the V 2p core levels. We also study the V 1s core level spectra of these compounds, which are possible only using hard X-rays and confirm the systematics in valence states of vanadium oxides. The temperature dependence of the low binding energy peak in V 1s spectra across the MI transition in V2O3 suggests an additional screening channel available in the Mott-Hubbard correlated metal phase. (c) 2005 Elsevier B.V. All rights reserved.
  • JJ Kim, H Makino, T Yao, Y Takata, K Kobayashi, T Yamamoto, T Hanada, MW Cho, E Ikenaga, A Yabashi, D Miwa, Y Nishino, K Tamasaku, T Ishikawa, S Shin
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 144 561 - 564 2005年06月 [査読有り][通常論文]
     
    Valence band spectra of Ga1-xCrxN have been investigated by high-energy photoemission spectroscopy at the photon energy of 5.95 keV Cr doping does introduce a novel electronic structure in the bandgap and causes some change in valence band structure. Based on the first-principle calculation, Cr-associated electronic levels in the bandgap, are assigned to nonbonding and antibonding d states while the change of the valence band suggests that the Ga 4s originated states are significantly modified through hybridization with the Cr 3d orbital. The present result evidences that the Ga valence electrons are considerably modified through the interaction with the second nearest-neighbour Cr atoms. (c) 2005 Elsevier B.V. All rights reserved.
  • K Horiba, M Taguchi, N Kamakura, K Yamamoto, A Chainani, Y Takata, E Ikenaga, H Namatame, A Taniguchi, A Awaji, A Takeuchi, D Miwa, Y Nishino, K Tamasaku, T Ishikawa, H Kumigashira, M Oshima, M Lippmaa, M Kawasaki, H Koinuma, K Kobayashi, S Shin
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 144 557 - 559 2005年06月 [査読有り][通常論文]
     
    In order to clarify the intrinsic bulk electronic structure of La1-xSrxMnO3 (LSMO) thin films, we have performed high-energy (hv = 5.95 keV) synchrotron photoemission spectroscopy (PES) of Mn 2p core-levels. In sharp contrast with the previous soft X-ray PES (h v = 800-1486.6 eV), the high-energy PES spectra exhibit a clear additional peak at the low binding-energy side of the Mn 2p(3/2) peak. To check for surface sensitivity, we measured take-off-angle dependence of Mn 2p core-levels. The results indicate that this additional peak originates from the bulk electronic structure. The peak shows a noticeable increase in the metallic phase of LSMO for x = 0.2 and 0.4, indicating that the origin of this peak is strongly related to the metallic physical properties of LSMO thin films. A single ion (MO6) cluster calculation including charge transfer from doping-induced states reproduces the new bulk-derived feature observed in Mn 2p core-levels. (c) 2005 Elsevier B.V. All rights reserved.
  • K Yamamoto, N Kamakura, M Taguchi, A Chainani, Y Takata, K Horiba, S Shin, E Ikenaga, K Mimura, M Shiga, H Wada, H Namatame, M Taniguchi, M Awaji, A Takeuchi, Y Nishino, D Miwa, K Tamasaku, T Ishikawa, K Kobayashi
    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 144 553 - 555 2005年06月 [査読有り][通常論文]
     
    The temperature-induced mixed valence transition in EuNi2(Si0.20Ge0.8)(2) has been investigated by hard X-ray (5940 eV) photoemission spectroscopy (HX-PES) for fractured surfaces, with a probing depth larger than 5 nm. The Eu 3d core-level states are studied below and above the critical valence transition temperature, T-v = 80 K. The FIX-PES spectra at 40 and 120 K show the mixed valence transition, with clear changes in the divalent and trivalent Eu 3d chemically shifted features. The Eu 3d HX-PES spectra indicate a mean valence of 2.70 +/- 0.03 at 40 K which changes to 2.40 +/- 0.03 at 120 K, in good accordance with the results of bulk Eu-III-edge X-ray absorption spectroscopy measurements. (c) 2005 Elsevier B.V. All rights reserved.
  • M Shimura, A Saito, S Matsuyama, T Sakuma, Y Terui, K Ueno, H Yumoto, K Yamauchi, K Yamamura, H Mimura, Y Sano, M Yabashi, K Tamasaku, K Nishio, Y Nishino, K Endo, K Hatake, Y Mori, Y Ishizaka, T Ishikawa
    CANCER RESEARCH 65 12 4998 - 5002 2005年06月 [査読有り][通常論文]
     
    Minerals are important for cellular functions, such as transcription and enzyme activity, and are also involved in the metabolism of anticancer chemotherapeutic compounds. Profiling of intracellular elements in individual cells could help in understanding the mechanism of drug resistance in tumors and possibly provide a new strategy of anticancer chemotherapy. Using a recently developed technique of scanning X-ray fluorescence microscopy (SXFM), we analyzed intracellular elements after treatment with cis-diamminedichloro-platinum(II) (CDDP), a platinum-based anticancer agent. The images obtained by SXFM (element array) revealed that the average Pt content of CDDP-resistant cells was 2.6 times less than that of sensitive cells, and the zinc content was inversely correlated with the intracellular Pt content. Data suggested that Zn-related detoxification is responsible for resistance to CDDP. Of Zn-related excretion factors, glutathione was highly correlated with the amount of Zn. The combined treatment of CDDP and a Zn(II) chelator resulted in the incorporation of thrice more Pt with the concomitant down-regulation of glutathione. We propose that the generation of an element array by SXFM opens up new avenues in cancer biology and treatment.
  • M Shimura, A Saito, S Matsuyama, T Sakuma, Y Terui, K Ueno, H Yumoto, K Yamauchi, K Yamamura, H Mimura, Y Sano, M Yabashi, K Tamasaku, K Nishio, Y Nishino, K Endo, K Hatake, Y Mori, Y Ishizaka, T Ishikawa
    CANCER RESEARCH 65 12 4998 - 5002 2005年06月 [査読有り][通常論文]
     
    Minerals are important for cellular functions, such as transcription and enzyme activity, and are also involved in the metabolism of anticancer chemotherapeutic compounds. Profiling of intracellular elements in individual cells could help in understanding the mechanism of drug resistance in tumors and possibly provide a new strategy of anticancer chemotherapy. Using a recently developed technique of scanning X-ray fluorescence microscopy (SXFM), we analyzed intracellular elements after treatment with cis-diamminedichloro-platinum(II) (CDDP), a platinum-based anticancer agent. The images obtained by SXFM (element array) revealed that the average Pt content of CDDP-resistant cells was 2.6 times less than that of sensitive cells, and the zinc content was inversely correlated with the intracellular Pt content. Data suggested that Zn-related detoxification is responsible for resistance to CDDP. Of Zn-related excretion factors, glutathione was highly correlated with the amount of Zn. The combined treatment of CDDP and a Zn(II) chelator resulted in the incorporation of thrice more Pt with the concomitant down-regulation of glutathione. We propose that the generation of an element array by SXFM opens up new avenues in cancer biology and treatment.
  • H Mimura, H Yumoto, S Matsuyama, K Yamamura, Y Sano, K Ueno, K Endo, Y Mori, M Yabashi, K Tamasaku, Y Nishino, T Ishikawa, K Yamauchi
    REVIEW OF SCIENTIFIC INSTRUMENTS 76 4 45102  2005年04月 [査読有り][通常論文]
     
    Metrology plays an important role in surface figuring with subnanometer accuracy. We have developed relative angle determinable stitching interferometry for the surface figuring of elliptical mirrors, in order to realize hard x-ray nanofocusing. In a stitching system, stitching angles are determined not by the general method using a common area between neighboring shots, but by the new method using the mirror's tilt angles measured at times when profile data are acquired. The high measurement accuracy of approximately 4 nm (peak-to-valley) was achieved in the measurement of a cylindrical surface having the same curvature as the elliptically designed shape to enable hard x-ray nanofocusing. (C) American Institute of Physics.
  • M Taguchi, A Chainani, N Kamakura, K Horiba, Y Takata, M Yabashi, K Tamasaku, Y Nishino, D Miwa, T Ishikawa, S Shin, E Ikenaga, T Yokoya, K Kobayashi, T Mochiku, K Hirata, K Motoya
    PHYSICAL REVIEW B 71 15 155102  2005年04月 [査読有り][通常論文]
     
    We report bulk-sensitive hard x-ray (h nu=5.95 keV) core-level photoemission spectroscopy (PES) of single crystal V1.98Cr0.02O3 and the high-T-c cuprate Bi2Sr2CaCu2O8+delta (Bi2212). V1.98Cr0.02O3 exhibits low binding energy "satellites" to the V 2p "main lines" in the metallic phase, which are suppressed in the antiferromagnetic insulator phase. In contrast, the Cu 2p spectra of Bi2212 do not show temperature-dependent features, but a comparison with soft x-ray PES indicates a large increase in the 2p(5)3d(9) satellites or 3d(9) weight in the bulk. Cluster model calculations, including a full multiplet structure and a screening channel derived from the coherent band at the Fermi energy, give very satisfactory agreement with the experiments.
  • AV Darahanau, AY Nikulin, A Souvorov, Y Nishino, BC Muddle, T Ishikawa
    PHYSICS LETTERS A 335 5-6 494 - 498 2005年02月 [査読有り][通常論文]
     
    X-ray Fraunhofer diffraction data have been collected from a series of weakly thickness-modulated samples using a synchrotron source. Three different 10 mum wide areas of a linear Fresnel zone structure etched in a silicon wafer were studied. Each studied area included different number of zones, ranging from 6 to 20. Phase retrieval X-ray diffractometry technique was used for the experimental data analysis. The zone structure thickness profiles were mapped with a spatial resolution of 100 nm. (C) 2005 Elsevier B.V. All rights reserved.
  • Mimura, H, Matsuyama, S, Yumoto, H, Hara, H, Yamamura, K, Sano, Y, Shibahara, M, End, K, Mori, Y, Nishino, Y, Tamasaku, K, Yabashi, M, Ishikawa, T, Yamauchi, K
    Japanese Journal of Applied Physics Part 2-Letters & Express Letters 44 16-19 L539 - L542 2005年 [査読有り][通常論文]
  • H. Mimura, H. Yumoto, S. Matsuyama, K. Yamamura, Y. Sano, K. Endo, Y. Mori, Y. Nishino, M. Yabashi, K. Tamasaku, T. Ishikawa, K. Yamauchi
    Proceedings of SPIE - The International Society for Optical Engineering 5921 1 - 8 2005年 [査読有り][通常論文]
     
    We developed the computer-controlled figuring system having controllability of removal depths with nanometer accuracy and spatial resolutions close to 0.1mm. In this system, Elastic Emission Machining (EEM) using nozzle-type EEM head and Microstitching Interferometry (MSI) are employed as a machining method and a figure measurement method. In EEM, very small stationary spot profiles ware obtained, selecting small circle nozzle aperture of a 0.15 mm diameter. Surface figuring is performed with controlling scanning speeds of sample stages, so that a measured profile turned into designed one. MSI, which was developed on the basis of interferometric stitching technologies, has reproducibility at subnanometer level and with spatial resolution of 0.03 mm. In this study, we demonstrated computer controlled figuring, focusing on removal of high frequency figurer errors. Figure accuracy of 0.2 nm (RMS) was achieved in a cross-section profile with a length of 90mm.
  • Satoshi Matsuyama, Hidekazu Mimura, Hirokatsu Yumoto, Hideyuki Hara, Kazuya Yamamura, Yasuhisa Sano, Katsuyoshi Endo, Yuzo Mori, Yoshinori Nishino, Kenji Tamasaku, Makina Yabashi, Tetsuya Ishikawa, Kazuto Yamauchia
    Proceedings of SPIE - The International Society for Optical Engineering 5918 1 - 8 2005年 [査読有り][通常論文]
     
    X-ray focusing techniques using Kirkpatrick and Baez mirrors are promising due to their capability of highly efficient and energy-tunable focusing. We have been developing a hard-X-ray focusing system using K-B mirrors for an X-ray microscope. Here, we report the development of a mirror manipulator and focusing tests using the manipulator. Mirror alignment tolerances were estimated using two types of simulators: a ray-trace simulator and a wave-optical simulator. On the basis of the simulation results, the mirror manipulator was developed achieving optimum K-B mirrors setup. The focal size was achieved to be 48 x 36nm2 (V x H) in FWHM at 1km long beamline of SPring-8. The obtained spatial resolution test results indicate that a scanning microscope with the focused beam can resolve the line-and-space patterns of 80nm line width in a high visibility of 60%.
  • K Horiba, M Taguchi, A Chainani, Y Takata, E Ikenaga, D Miwa, Y Nishino, K Tamasaku, M Awaji, A Takeuchi, M Yabashi, H Namatame, M Taniguchi, H Kumigashira, M Oshima, M Lippmaa, M Kawasaki, H Koinuma, K Kobayashi, T Ishikawa, S Shin
    PHYSICAL REVIEW LETTERS 93 23 236401  2004年12月 [査読有り][通常論文]
     
    Using hard x-ray (HX; hnu=5.95 keV) synchrotron photoemission spectroscopy (PES), we study the intrinsic electronic structure of La1-xSrxMnO3 (LSMO) thin films. Comparison of Mn 2p core-levels with soft x-ray (SX; hnusimilar to1000 eV) PES shows a clear additional well-screened feature only in HX PES. Takeoff-angle dependent data indicate its bulk (greater than or equal to20 Angstrom) character. The doping and temperature dependence track the ferromagnetism and metallicity of the LSMO series. Cluster model calculations including charge transfer from doping-induced states show good agreement, confirming this picture of bulk properties reflected in Mn 2p core-levels using HX PES.
  • H Sato, K Shimada, M Arita, K Hiraoka, K Kojima, Y Takeda, K Yoshikawa, M Sawada, M Nakatake, H Namatame, M Taniguchi, Y Takata, E Ikenaga, S Shin, K Kobayashi, K Tamasaku, Y Nishino, D Miwa, M Yabashi, T Ishikawa
    PHYSICAL REVIEW LETTERS 93 24 246404  2004年12月 [査読有り][通常論文]
     
    Yb 3d and valence-band photoemission spectra of the first-order valence-transition compound YbInCu4 have been measured with hard x ray at an excitation energy of 5.95 keV. Abrupt changes are clearly observed in both spectra around the transition temperature T-V=42 K, in comparison with ultraviolet and soft x-ray photoemission (VUV-PES and SX-PES) spectra. From the Yb 3d spectra, the Yb valence has been estimated to be similar to2.90 from 220 down to 50 K and similar to2.74 at 30-10 K. We propose that Yb 3d hard x-ray photoemission spectroscopy is a very powerful method to estimate the valence of Yb with high accuracy. On the other hand, the Yb2+ 4f-derived peaks in the valence-band spectra exhibit a remarkable enhancement below T-V. The shape of the valence-band spectra is different from those of the VUV-PES and SX-PES spectra above T-V, reflecting the In 5s and 5p contributions.
  • N Kamakura, M Taguchi, A Chainani, Y Takata, K Horiba, K Yamamoto, K Tamasaku, Y Nishino, D Miwa, E Ikenaga, M Awaji, A Takeuchi, H Ohashi, Y Senba, H Namatame, M Taniguchi, T Ishikawa, K Kobayashi, S Shin
    EUROPHYSICS LETTERS 68 4 557 - 563 2004年11月 [査読有り][通常論文]
     
    We study the Mott-Hubbard metal-insulator transition in single-crystal V2O3 usinghard X-ray (HX : hv = 5940 eV) core-level photoemission spectroscopy ( PES). HX-PES enables a bulk probe of the electronic structure in the paramagnetic metallic and antiferromagnetic insulating phases. Metallic V2O3 shows additional features at low binding energy to the main peak of V 1s, 2p, and 3s core levels, which vanish in the insulating phase. The low-binding-energy features in the metallic phase are also observed using soft X-rays (SX : hv = 1450 eV), but with a reduced relative intensity compared to the HX-PES spectrum. A model cluster calculation including core hole screening by coherent states at the Fermi level, reproduces the low-binding-energy features in the metallic phase. The O 1s core level also shows spectral changes: the asymmetric line shape in the metallic phase transforms to a symmetric line shape in the insulating phase, consistent with the metal-insulator transition. The results indicate screening by coherent states is more effective in the bulk compared to the surface. HX-PES is, thus, a reliable probe of the electronic-structure changes across the metal-insulator transition in strongly correlated electron systems.
  • JJ Kim, H Makino, K Kobayashi, Y Takata, T Yamamoto, T Hanada, MW Cho, E Ikenaga, M Yabashi, D Miwa, Y Nishino, K Tamasaku, T Ishikawa, S Shin, T Yao
    PHYSICAL REVIEW B 70 16 161315  2004年10月 [査読有り][通常論文]
     
    We observed that Cr doping introduces an electronic state in the band gap in Ga1-xCrxN by using hard x-ray photoemission spectroscopy. Based on first-principles calculations, the electronic state is interpreted to be dominantly Ga 4s originated states. The chemical effect of Cr up to the second-nearest-neighbor Ga atoms has also been observed in the core-level spectra of Ga 2p(3/2). The present results evidence that the Ga valence electrons are strongly affected by the second-nearest-neighbor Cr atoms through Cr 3d-Ga 4s hybridization.
  • K Yamamoto, M Taguchi, N Kamakura, K Horiba, Y Takata, A Chainani, S Shin, E Ikenaga, K Mimura, M Shiga, H Wada, H Namatame, M Taniguchi, M Awaji, A Takeuchi, Y Nishino, D Miwa, T Ishikawa, K Kobayashi
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 73 10 2616 - 2619 2004年10月 [査読有り][通常論文]
     
    We investigate the temperature-induced mixed valence transition in EuNi2(Si0.20Ge0.80)(2) using Hard X-ray (5940 eV) photoemission spectroscopy (HX-PES), with a probing depth larger than 5 nm. The Eu 3d, Ni 2p and Ge 2p core-level states are studied below and above the critical valence transition temperature, T-v = 80 K. HX-PES spectra at 40 K and 120 K show the mixed valence transition, with clear changes in the divalent and trivalent Eu 3d chemically shifted features, and negligible changes in the Ni 2p and Ge 2p states. The Eu 3d spectral shapes match very well with the results of the atomic calculations of the Eu2+ and Eu3+ configurations, confirming intra-atomic multiplet features. The Eu 3d HX-PES spectra indicate a mean valence of 2.70 +/- 0.03 at 40 K which changes to 2.40 +/- 0.03 at 120 K, in good accord with the results of bulk Eu L-edge X-ray absorption spectroscopy measurements.
  • J. J. Kim, H. Makino, K. Kobayashi, Y. Takata, T. Yamamoto, T. Hanada, M. W. Cho, E. Ikenaga, M. Yabashi, D. Miwa, Y. Nishino, K. Tamasaku, T. Ishikawa, S. Shin, T. Yao
    Physical Review B - Condensed Matter and Materials Physics 70 16 1 - 4 2004年10月 [査読有り][通常論文]
     
    We observed that Cr doping introduces an electronic state in the band gap in Ga1-xCrxN by using hard x-ray photoemission spectroscopy. Based on first-principles calculations, the electronic state is interpreted to be dominantly Ga 4s originated states. The chemical effect of Cr up to the second-nearest-neighbor Ga atoms has also been observed in the core-level spectra of Ga 2p3/2. The present results evidence that the Ga valence electrons are strongly affected by the second-nearest-neighbor Cr atoms through Cr 3d-Ga 4s hybridization.
  • JP Sutter, T Ishikawa, U Kuetgens, G Materlik, Y Nishino, A Rostomyan, K Tamasaku, M Yabashi
    JOURNAL OF SYNCHROTRON RADIATION 11 5 378 - 385 2004年09月 [査読有り][通常論文]
     
    A new X-ray Michelson interferometer based on the BBB interferometer of Bonse and Hart and designed for X-rays of wavelength similar to1 Angstrom was described in a previous paper. Here, a further test carried out at the SPring-8 1 km beamline BL29XUL is reported. One of the BBB's mirrors was displaced by a piezo to introduce the required path-length difference. The resulting variation of intensity with piezo voltage as measured by an avalanche photodiode could be ascribed to the phase variation resulting from the path-length change, with a small additional contribution from the change of the position of the lattice planes of the front mirror relative to the rest of the crystal. This 'Michelson fringe' interpretation is supported by the observed steady movement across the output beam of the interference fringes produced by a refractive wedge when the piezo voltage was ramped. The front-mirror displacement required for one complete fringe at the given wavelength is only 0.675 Angstrom; therefore, a quiet environment is vital for operating this device, as previous experiments have shown.
  • H Sato, K Shimada, M Arita, Y Takeda, M Sawada, M Nakatake, K Yoshikawa, H Namatame, Y Takata, K Kobayashi, E Ikenega, S Shin, M Yabashi, D Miwa, Y Nishino, K Tamasaku, T Ishikawa, K Hiraoka, K Kojima, M Taniguchi
    PHYSICA B-CONDENSED MATTER 351 3-4 298 - 300 2004年09月 [査読有り][通常論文]
     
    Yb 3d and valence-band photoemission spectra of YbInCu4 have been measured at hv = 5.95 keV. Abrupt changes are observed in both spectra, reflecting the valence transition at Tv = 42 K. The Yb valence estimated from the Yb 3d spectra is zsimilar to2.90 at 220-50K and sharply decreases to zsimilar to2.74 at 30-10K. (C) 2004 Elsevier B.V. All rights reserved.
  • Y Takeda, M Arita, M Higashiguchi, K Shimada, M Sawada, H Sato, M Nakatake, H Namatame, M Taniguchi, F Iga, T Takabatake, K Takata, E Ikenaga, M Yabashi, D Miwa, Y Nishino, K Tamasaku, T Ishikawa, S Shin, K Kobayashi
    PHYSICA B-CONDENSED MATTER 351 3-4 286 - 288 2004年09月 [査読有り][通常論文]
     
    The temperature dependences of the Yb 4f and 3d states of Kondo semiconductor YbB12 single crystal have been studied by high-resolution photoemission spectroscopy taken at hv = 100 and 5951 eV. The Yb2+ 4f(7/2) state at the Fermi level is enhanced on cooling. With improved energy resolution, we discover an additional quasi-particle peak at 15 meV that developes below 60 K. From the Yb 3d spectrum at 22 K, the Yb valence is estimated to be similar to2.88. (C) 2004 Elsevier B.V. All rights reserved.
  • H Mimura, K Yamauchi, K Yamamura, A Kubota, S Matsuyama, Y Sano, K Ueno, K Endo, Y Nishino, K Tamasaku, M Yabashi, T Ishikawa, Y Mori
    JOURNAL OF SYNCHROTRON RADIATION 11 4 343 - 346 2004年07月 [査読有り][通常論文]
     
    A new figure correction method has been applied in order to fabricate an elliptical mirror to realize a one-dimensionally diverging X-ray beam having high image quality. Mutual relations between figure errors and intensity uniformities of diverging X-ray beams have also been investigated using a wave-optical simulator and indicate that figure errors in relatively short spatial wavelength ranges lead to high-contrast interference fringes. By using a microstitching interferometer and elastic emission machining, figure correction of an elliptical mirror with a lateral resolution close to 0.1 mm was carried out. A one-dimensional diverging X-ray obtained using the fabricated mirror was observed at SPring-8 and evaluated to have a sufficiently flat intensity distribution.
  • Chainani, A, Yokoya, T, Takata, Y, Tamasaku, K, Taguchi, M, Shimojima, T, Kamakura, N, Horiba, K, Tsuda, S, Shin, S, Miwa, D, Nishino, Y, Ishikawa, T, Yabashi, M, Kobayashi, K, Namatame, H, Taniguchi, M, Takada, K, Sasaki, T, Sakurai, H, Takayama-Muromachi, E
    Physical Review B 69 18 180508  2004年05月 [査読有り][通常論文]
  • A Chainani, T Yokoya, Y Takata, K Tamasaku, M Taguchi, T Shimojima, N Kamakura, K Horiba, S Tsuda, S Shin, D Miwa, Y Nishino, T Ishikawa, M Yabashi, K Kobayashi, H Namatame, M Taniguchi, K Takada, T Sasaki, H Sakurai, E Takayama-Muromachi
    PHYSICAL REVIEW B 69 18 2004年05月 [査読有り][通常論文]
     
    High-energy (hnu=5.95 keV) synchrotron photoemission spectroscopy (PES) is used to study bulk electronic structure of Na0.35CoO2.1.3H(2)O, the layered superconductor. In contrast to three-dimensional doped Co oxides, Co 2p core level spectra show well-separated Co3+ and Co4+ ions. Cluster calculations suggest low-spin Co3+ and Co4+ character, and a moderate on-site Coulomb correlation energy U(dd)similar to3-5.5 eV. Photon dependent valence band PES identifies Co 3d and O 2p derived states, in near agreement with band-structure calculations.
  • A. Chainani, T. Yokoya, Y. Takata, K. Tamasaku, M. Taguchi, T. Shimojima, N. Kamakura, K. Horiba, S. Tsuda, S. Shin, S. Shin, D. Miwa, Y. Nishino, T. Ishikawa, M. Yabashi, K. Kobayashi, H. Namatame, M. Taniguchi, K. Takada, K. Takada, T. Sasaki, T. Sasaki, H. Sakurai, E. Takayama-Muromachi
    Physical Review B - Condensed Matter and Materials Physics 69 18 1 - 180508 2004年05月 [査読有り][通常論文]
     
    High-energy (hv = 5.95 keV) synchrotron photoemission spectroscopy (PES) is used to study bulk electronic structure of Na0.35CoO2· 1.3H2O, the layered superconductor. In contrast to three-dimensional doped Co oxides, Co 2p core level spectra show well-separated Co3+and Co4+ions. Cluster calculations suggest low-spin Co3+and Co4+character, and a moderate on-site Coulomb correlation energy Udd∼3-5.5 eV. Photon dependent valence band PES identifies Co 3d and O 2p derived states, in near agreement with band-structure calculations.
  • Fabrication technology for hard X-ray reflective optics
    Y. Mori, K. Yamuchi, K. Yamamura, H. Mimura, Y.Sano, S. Matsuyama, K. Endo, Y. Nishino, K. Tamasaku, M. Yabashi, T. Ishikawa
    Proceedings of Second International Workshop on Metrology for X-ray Optics 2004年03月 [査読無し][通常論文]
  • S Matsuyama, H Mimura, K Yamamura, H Yumoto, Y Sano, K Endo, Y Mori, M Yabashi, K Tamasaku, Y Nishino, T Ishikawa, K Yamauchi
    ADVANCES IN MIRROR TECHNOLOGY FOR X-RAY, EUV LITHOGRAPHY, LASER, AND OTHER APPLICATIONS II 5533 181 - 191 2004年 [査読有り][通常論文]
     
    The spatial resolution of the scanning X-ray microscopy apparently depends on the beam size of the focused X-ray. Recently, highly accurate elliptical mirrors were reported to be fabricated, and nearly diffraction-limited line focusing was achieved. In this study, to realize diffraction-limited and 2-dimentional focusing with such highly accurate mirrors, accuracies to be realized in mirror alignings, for example, adjusting the glancing angle and the in-plane rotation, were estimated by employing two types of simulators. They are appropriately based on geometrical or wave-optical theories. They are alternatively employed according to the degree of accuracy required in the mirror alignment. A focusing unit with the adjusting mechanism fulfilling the required alignment accuracies was constructed, and the relationships between the alignment errors and focused beam profiles were quantitatively examined at the 1km-long beamline (BL29XUL) of SPring-8. Obtained results were in good agreement with the calculated results. Additionally, the alignment accuracy to be realized in the K-B unit equipping mirrors of larger NA (numerical aperture) was calculated to realize sufficient performances in focusing.
  • K Yamauchi, K Yamamura, H Mimura, Y Sano, S Matsuyama, H Yumoto, K Ueno, M Shibahara, K Endo, M Yabashi, K Tamasaku, Y Nishino, T Ishikawa, Y Mori
    ADVANCES IN MIRROR TECHNOLOGY FOR X-RAY, EUV LITHOGRAPHY, LASER, AND OTHER APPLICATIONS II 5533 116 - 123 2004年 [査読有り][通常論文]
     
    In our previous study, we realized a hard X-ray focused beam having a 180nmx90nm focal size using fabricated elliptical mirrors. In this study, to realize a smaller focal size, more steeply curved elliptical mirrors with platinum-coated surfaces were fabricated. We showed that aspheric quality mirrors can be manufactured with recently developed machining methods. We carried out line focusing tests on the elliptical mirror at the 1-km-long beamline of SPring-8. A full width at half maximum of 40 rim. was achieved in the focal beam profile under the best focusing conditions. Keyword: ultraprecision machining, X-ray mirror, plasma CVM (chemical vaporization machining), EEM (elastic emission machining), coherent X-ray, hard X-ray focusing, microstitching interferomatory
  • Y Nishino, T Ishikawa
    SYNCHROTRON RADIATION INSTRUMENTATION 705 1078 - 1081 2004年 [査読有り][通常論文]
     
    piXAFS (photon interference x-ray absorption fine structure) is a structure in x-ray absorption spectra due to incident photon interference. Fourier analysis of piXAFS provides radial distribution of atoms in the absorber. piXAFS extends in a wide photon energy range across absorption edges, and therefore it is possible to carry out x-ray absorption spectroscopy for light elements with hard x-rays. It is of great advantage because measurements can be performed comfortably in air. We successfully measured piXAFS for silicon powder in the hard x-ray region.
  • H Mimura, H Yumoto, S Matsuyama, K Yamamura, Y Sano, K Ueno, K Endo, Y Mori, M Yabashi, K Tamasaku, Y Nishino, T Ishikawa, K Yamauchi
    ADVANCES IN MIRROR TECHNOLOGY FOR X-RAY, EUV LITHOGRAPHY, LASER, AND OTHER APPLICATIONS II 5533 171 - 180 2004年 [査読有り][通常論文]
     
    Metrology plays more important role than machining in surface figuring at sub-nanometer accuracy. The microstitching interferometry based on a microscopic interferometer having peak-to-valley (p-v) height accuracy of sub-nanometer order and lateral resolution higher than 20 gm was developed to measure surface figures of X-ray mirror optics. In addition, the relative angle determinable stitching interferometry was also developed to measure surface profiles of elliptical mirrors to realize hard X-ray nanofocusing. By combining the two interferometies, the absolute measurement accuracy of approximately 3 nm (peak-to-valley) was achieved in the measurement of a cylindrical surface having the same curvature as the elliptically designed shape to enable nanofocusing.
  • Y Nishino, JW Miao, T Ishikawa
    PHYSICAL REVIEW B 68 22 220101  2003年12月 [査読有り][通常論文]
     
    X-ray-diffraction microscopy images nanocrystals and nonperiodic objects by directly reconstructing from oversampled diffraction intensities. Successful image reconstruction of nonperiodic objects has so far required additional experiments to supplement the missing data in the diffraction intensities. Reconstruction only from diffraction data is desirable. We show that image reconstruction of nonperiodic objects can be done without any supplemental experiments by applying a modified hybrid input-output algorithm to experimental hard x-ray-diffraction data of a nanostructured pattern.
  • JW Miao, KO Hodgson, T Ishikawa, CA Larabell, MA LeGros, Y Nishino
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 100 1 110 - 112 2003年01月 [査読有り][通常論文]
     
    We report the first experimental recording, to our knowledge, of the diffraction pattern from intact Escherichia coli bacteria using coherent x-rays with a wavelength of 2 A. By using the oversampling phasing method, a real space image at a resolution of 30 nm was directly reconstructed from the diffraction pattern. An R factor used for characterizing the quality of the reconstruction was in the range of 5%, which demonstrated the reliability of the reconstruction process. The distribution of proteins inside the bacteria labeled with manganese oxide has been identified and this distribution confirmed by fluorescence microscopy images. Compared with lens-based microscopy, this diffraction-based imaging approach can examine thicker samples, such as whole cultured cells, in three dimensions with resolution limited only by radiation damage. Looking forward, the successful recording and reconstruction of diffraction patterns from biological samples reported here represent an important step toward the potential of imaging single biomolecules at near-atomic resolution by combining single-particle diffraction with x-ray free electron lasers.
  • Jianwei Miao, Keith O. Hodgson, James E. Amonette, Yoshinori Nishino, Tetsuya Ishikawa, Keith O. Hodgson
    Physical Review B - Condensed Matter and Materials Physics 68 1 12201  2003年 [査読有り][通常論文]
     
    We report the development of a novel experimental approach to the direct determination of the absolute electron density of nanostructured and disordered materials. By calibrating the incident coherent x-ray flux and the diffraction pattern intensity and using the oversampling method, we have directly determined the absolute electron density of a porous silica particle at ∼9-nm resolution. This general approach can be used for the quantitative characterization of nanocrystals and noncrystalline materials at nanometer or better resolution. © 2003 The American Physical Society.
  • Y Nishino, T Kudo, M Suzuki, T Ishikawa
    CRYSTALS, MULTILAYERS, AND OTHER SYNCHROTRON OPTICS 5195 94 - 103 2003年 [査読有り][通常論文]
     
    The stability of synchrotron beamline optics is required in experiments using x-ray coherence. Especially the stability of a monochromator is important in considering a high heat load due to exposure to intense polychromatic x-rays. We developed MOSTAB (monochromator stabilization) modules and carried out performance tests using SPring-8 beamlines. We succeeded in the simultaneous stabilization of the monochromatic x-ray beam intensity and position with MOSTAB. An attempt was also made to stabilize the x-ray beam at the 1 km experimental station at SPring-8.
  • MIAO J, AMONETTE JE, NISHINO Y
    PHYSICAL REVIEW B 68 1 2003年 [査読有り][通常論文]
  • JW Miao, KO Hodgson, T Ishikawa, CA Larabell, MA LeGros, Y Nishino
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 100 1 110 - 112 2003年01月 [査読有り][通常論文]
     
    We report the first experimental recording, to our knowledge, of the diffraction pattern from intact Escherichia coli bacteria using coherent x-rays with a wavelength of 2 A. By using the oversampling phasing method, a real space image at a resolution of 30 nm was directly reconstructed from the diffraction pattern. An R factor used for characterizing the quality of the reconstruction was in the range of 5%, which demonstrated the reliability of the reconstruction process. The distribution of proteins inside the bacteria labeled with manganese oxide has been identified and this distribution confirmed by fluorescence microscopy images. Compared with lens-based microscopy, this diffraction-based imaging approach can examine thicker samples, such as whole cultured cells, in three dimensions with resolution limited only by radiation damage. Looking forward, the successful recording and reconstruction of diffraction patterns from biological samples reported here represent an important step toward the potential of imaging single biomolecules at near-atomic resolution by combining single-particle diffraction with x-ray free electron lasers.
  • Nishino, Y, Ishikawa, T, Hayashi, K, Takahashi, Y, Matsubara, E
    Physical Review B 66 9 92105  2002年09月01日 [査読有り][通常論文]
  • Y Nishino, T Ishikawa, M Suzuki, N Kawamura, P Kappen, P Korecki, N Haack, G Materlik
    PHYSICAL REVIEW B 66 11 113103  2002年09月 [査読有り][通常論文]
     
    We consider fundamental structures in x-ray absorption spectra over a wide energy range. We formulate the elastic scattering in addition to the photoelectric absorption in recently reported photon interference x-ray absorption fine structure (piXAFS). The simulations show excellent agreement with experimental x-ray absorption spectra for platinum and tungsten powders far above and below the L absorption edges. piXAFS can be as big as in the order of 10% of XAFS, and cannot be easily neglected in detailed analysis of XAFS and related phenomena.
  • Y Nishino, T Ishikawa, K Hayashi, Y Takahashi, E Matsubara
    PHYSICAL REVIEW B 66 9 2002年09月 [査読有り][通常論文]
     
    We propose a two-energy twin image removal algorithm for atomic-resolution x-ray holography. The validity of the algorithm is shown in a theoretical simulation and in an experiment of internal detector x-ray holography using a ZnSe single crystal. The algorithm, compared to the widely used multiple-energy algorithm, allows efficient measurement of holograms, and is especially important when the available x-ray energies are fixed. It enables twin image free holography using characteristic x rays from laboratory generators and x-ray pulses of free-electron lasers.
  • Nishino, Y, Troger, L, Korecki, R, Materlik, G
    Physical Review B 64 20 201101  2001年11月15日 [査読有り][通常論文]
  • Y Nishino, L Troger, P Korecki, G Materlik
    PHYSICAL REVIEW B 64 20 2001年11月 [査読有り][通常論文]
     
    We report about a fine structure in x-ray absorption spectra, named photon interference x-ray absorption fine structure (pi XAFS). pi XAFS is due to the interference of x-rays inside the sample and extends across absorption edges. Using a platinum foil pi XAFS was measured in a high precision absorption experiment. Excellent agreement with a theoretical pi XAFS simulation is achieved in the energy range for above an absorption edge where photoelectron XAFS is negligible. pi XAFS provides a method for determination of atomic structure on short- and long-range order scale.
  • B Adams, Y Nishino, DV Novikov, G Materlik, DM Mills
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 467 2 1019 - 1020 2001年07月 [査読有り][通常論文]
     
    Parametric down conversion of X-ray photons in diamond crystals was detected in six experiments, all using the phase matching scheme first employed in the X-ray regime by Eisenberger and McCall (Eisenberger and McCall, Phys. Rev. Lett. 26 (1971) 684). The conversion events were detected by a combination of time correlation spectroscopy and energy discrimination. The time correlation spectra gave a direct comparison of the conversion rate over the accidental coincidence rate. (C) 2001 Elsevier Science B.V. All rights reserved.
  • B Adams, Y Nishino, DV Novikov, G Materlik, DM Mills
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 467 1019 - 1020 2001年07月 [査読有り][通常論文]
     
    Parametric down conversion of X-ray photons in diamond crystals was detected in six experiments, all using the phase matching scheme first employed in the X-ray regime by Eisenberger and McCall (Eisenberger and McCall, Phys. Rev. Lett. 26 (1971) 684). The conversion events were detected by a combination of time correlation spectroscopy and energy discrimination. The time correlation spectra gave a direct comparison of the conversion rate over the accidental coincidence rate. (C) 2001 Elsevier Science B.V. All rights reserved.
  • Y Nishino, G Materlik
    JOURNAL OF SYNCHROTRON RADIATION 8 2 204 - 206 2001年03月 [査読有り][通常論文]
     
    The theory of photon interference x-ray absorption fine structure (pi XAFS) is described. Due to coherent x-ray scattering from atoms, a spatial variation of the x-ray intensity is produced inside the sample. The intensity at the x-ray absorbing atom changes according to the incident energy. Thus pi XAFS in extended absorption spectra is produced. It extends in a wide energy range over absorption edges. For powders the pi XAFS formula has equivalent form as the EXAFS formula, and the Fourier transform provides distances of neighboring atoms from the absorbing atom. Due to a long mean free path of the photon, pi XAFS for powders contains sharp structures. They are explained as a crystal grain orientation averaging of the x-ray standing wave effect.
  • L Troger, P Kappen, Y Nishino, N Haack, G Materlik
    JOURNAL OF SYNCHROTRON RADIATION 8 2 105 - 109 2001年03月 [査読有り][通常論文]
     
    Experimental data are presented which demonstrate the existence of a fine structure in extended X-ray absorption spectra due to interference effects in the initial photon state (pi XAFS). Interference occurs between the incident electromagnetic wave and its coherently scattered waves from neighboring atoms. Using fine platinum and tungsten powders as well as polycrystalline platinum foil, pi XAFS was measured in high-precision absorption experiments at beamline X1 at HASYLAB/DESY over a wide energy range. pi XAFS is observed below and above absorption-edge positions in both transmission and total-electron-yield detection. Based on experimental data it is shown that pi XAFS is sensitive to geometric atomic structure. Fourier-transformed pi XAFS data carry information, comparable with that of EXAFS, about the short-range-order structure of the sample. Sharp structures occur in pi XAFS when a Bragg backscattering condition of the incident X-rays is fulfilled. They allow precise measurement of long-range-order structural information. Measured data are compared with simulations based on pi XAFS theory. Although pi XAFS structures are similarly observed in two detection techniques, the importance of scattering off the sample for the measurements needs to be investigated further. Disentangling pi XAFS, multielectron photoexcitations and atomic XAFS in high-precision measurements close to absorption edges poses a challenge for future studies.
  • L Troger, P Kappen, Y Nishino, N Haack, G Materlik
    JOURNAL OF SYNCHROTRON RADIATION 8 105 - 109 2001年03月 [査読有り][通常論文]
     
    Experimental data are presented which demonstrate the existence of a fine structure in extended X-ray absorption spectra due to interference effects in the initial photon state (pi XAFS). Interference occurs between the incident electromagnetic wave and its coherently scattered waves from neighboring atoms. Using fine platinum and tungsten powders as well as polycrystalline platinum foil, pi XAFS was measured in high-precision absorption experiments at beamline X1 at HASYLAB/DESY over a wide energy range. pi XAFS is observed below and above absorption-edge positions in both transmission and total-electron-yield detection. Based on experimental data it is shown that pi XAFS is sensitive to geometric atomic structure. Fourier-transformed pi XAFS data carry information, comparable with that of EXAFS, about the short-range-order structure of the sample. Sharp structures occur in pi XAFS when a Bragg backscattering condition of the incident X-rays is fulfilled. They allow precise measurement of long-range-order structural information. Measured data are compared with simulations based on pi XAFS theory. Although pi XAFS structures are similarly observed in two detection techniques, the importance of scattering off the sample for the measurements needs to be investigated further. Disentangling pi XAFS, multielectron photoexcitations and atomic XAFS in high-precision measurements close to absorption edges poses a challenge for future studies.
  • B Adams, Y Nishino, G Materlik
    JOURNAL OF SYNCHROTRON RADIATION 7 4 274 - 279 2000年07月 [査読有り][通常論文]
     
    A new experimental technique for reciprocal X-ray holography has been developed. The experimental set-up makes it possible to measure a reciprocal hologram without unwanted mixture of the X-ray fluorescence holography signal. The data are recorded during continuous rotation of the sample, and are accumulated over many revolutions. Thus the sensitivity to fluctuations of the source characteristics is reduced. A very high resolution over a large angular range is also achieved, which allows recording of X-ray standing-wave shapes near Bragg angles. The reconstruction of the measured hologram of a Cu(3)Au crystal gives positions of the nearest and next-nearest neighbours of a fluorescing Cu atom.
  • B Adams, Y Nishino, G Materlik
    JOURNAL OF SYNCHROTRON RADIATION 7 274 - 279 2000年07月 [査読有り][通常論文]
     
    A new experimental technique for reciprocal X-ray holography has been developed. The experimental set-up makes it possible to measure a reciprocal hologram without unwanted mixture of the X-ray fluorescence holography signal. The data are recorded during continuous rotation of the sample, and are accumulated over many revolutions. Thus the sensitivity to fluctuations of the source characteristics is reduced. A very high resolution over a large angular range is also achieved, which allows recording of X-ray standing-wave shapes near Bragg angles. The reconstruction of the measured hologram of a Cu(3)Au crystal gives positions of the nearest and next-nearest neighbours of a fluorescing Cu atom.
  • Nishino, Y, Materlik, G
    Physical Review B 61 21 14845 - 14845 2000年06月01日 [査読有り][通常論文]
  • B Adams, T Hiort, G Materlik, Y Nishino, DV Novikov
    X-RAY AND INNER-SHELL PROCESSES 506 549 - 564 2000年 [査読有り][通常論文]
     
    The current state of atomic resolution x-ray holography is discussed on the basis of theory and experimental results. X-ray holography is theoretically described in quantum theory. Presently-used experimental implementations are shown together with the data analysis used. Reconstructions of experimental and simulated holograms are compared for a Cu3Au crystal structure. Rigorous experimental realizations of pure direct and reciprocal x-ray holography methods are demonstrated, and future developments and applications of the method are suggested.
  • H. Okamura, J. Kawahara, T. Nanba, S. Kimura, K. Soda, U. Mizutani, Y. Nishino, M. Kato, I. Shimoyama, H. Miura, K. Fukui, K. Nakagawa, H. Nakagawa, T. Kinoshita
    Physical Review Letters 84 16 3674 - 3677 2000年 [査読無し][通常論文]
     
    Optical conductivity data of the intermetallic compounds (Fe1-xVx)3Al (0≤x≤0.33) reveal that their density of states around the Fermi energy (EF) is strongly reduced as x is increased. In particular, Fe2VAl (x = 0.33) has a deep, well-developed pseudogap of 0.1–0.2eV at EF and a small density (˜5×1020cm-3) of carriers, which is highly unusual for intermetallic compounds. It is shown that the pseudogap results from the band structure of Fe2VAl, rather than from temperature-dependent correlation effects. Based on the present results, we propose a simple model that consistently explains both the semiconductorlike transport and the metallic photoemission results previously observed for Fe2VAl. © 2000 The American Physical Society.
  • NISHINO Y, MATERLIK
    PHYSICAL REVIEW B 61 21 14845  2000年 [査読有り][通常論文]
  • Y Nishino, G Materlik
    PHYSICAL REVIEW B 60 22 15074 - 15083 1999年12月 [査読有り][通常論文]
     
    We calculate the cross section of the photoionization process consistently in the framework of quantum electrodynamics, including the initial-state photon interaction and the final-state photoelectron interaction with neighboring atoms. The obtained photoionization cross section explains multiple energy x-ray holography (MEXH), photoelectron holography, and extended x-ray absorption fine structure (EXAFS). In EXAFS, the contribution of the initial-state photon interaction is found to oscillate with energy and can disturb the EXAFS signal. It becomes non-negligible at higher energies. At 1 keV above the absorption edge, it can be in comparable order of the EXAFS signal. The hologram functions of MEXH and x-ray fluorescence holography are consistent with those in classical electrodynamics. [S0163-1829(99)02546-1].
  • Y Nishino, G Materlik
    PHYSICAL REVIEW B 60 22 15074 - 15083 1999年12月 [査読有り][通常論文]
     
    We calculate the cross section of the photoionization process consistently in the framework of quantum electrodynamics, including the initial-state photon interaction and the final-state photoelectron interaction with neighboring atoms. The obtained photoionization cross section explains multiple energy x-ray holography (MEXH), photoelectron holography, and extended x-ray absorption fine structure (EXAFS). In EXAFS, the contribution of the initial-state photon interaction is found to oscillate with energy and can disturb the EXAFS signal. It becomes non-negligible at higher energies. At 1 keV above the absorption edge, it can be in comparable order of the EXAFS signal. The hologram functions of MEXH and x-ray fluorescence holography are consistent with those in classical electrodynamics. [S0163-1829(99)02546-1].
  • B Adams, T Hiort, E Kossel, G Materlik, Y Nishino, DV Novikov
    PHYSICA STATUS SOLIDI B-BASIC RESEARCH 215 1 757 - 771 1999年09月 [査読有り][通常論文]
     
    The current state of atomic resolution X-ray holography is discussed on the basis of theoretical simulations and experimental results. The dependence of the spatial resolution on photon energy and angular scan ranges are studied, and presently-used experimental implementations are described together with the data analysis used. Reconstructions of simulated and experimental holograms are compared for a Cu3Au crystal structure. Rigorous experimental realizations of pure direct and reciprocal X-ray holography methods are demonstrated, and future developments and applications of the method are suggested.
  • B Adams, T Hiort, E Kossel, G Materlik, Y Nishino, DV Novikov
    PHYSICA STATUS SOLIDI B-BASIC RESEARCH 215 1 757 - 771 1999年09月 [査読有り][通常論文]
     
    The current state of atomic resolution X-ray holography is discussed on the basis of theoretical simulations and experimental results. The dependence of the spatial resolution on photon energy and angular scan ranges are studied, and presently-used experimental implementations are described together with the data analysis used. Reconstructions of simulated and experimental holograms are compared for a Cu3Au crystal structure. Rigorous experimental realizations of pure direct and reciprocal X-ray holography methods are demonstrated, and future developments and applications of the method are suggested.
  • Y Kondo, O Morimatsu, Y Nishino
    AUSTRALIAN JOURNAL OF PHYSICS 50 1 221 - 231 1997年 [査読有り][通常論文]
     
    Hadron-nucleon scattering lengths are studied by the QCD sum rule. First we explain our motivation and present the formulation for calculating hadron-nucleon scattering lengths by the QCD sum rule, where the relation between the hadron mass in the nuclear medium and the hadron-nucleon scattering length is also clarified. Secondly we discuss two applications, the pion-nucleon scattering lengths and the nucleon-nucleon scattering lengths. In the case of the pion-nucleon scattering length we show that the results of the QCD sum rule are consistent with the low-energy theorem. In the case of the nucleon-nucleon scattering lengths we show that the results of the QCD sum rule are in qualitative agreement with experiment.
  • Y Kondo, O Morimatsu, Y Nishino
    PHYSICAL REVIEW C 53 4 1927 - 1935 1996年04月 [査読有り][通常論文]
     
    The pion-nucleon and kaon-nucleon scattering lengths are studied in the QCD sum rule. We show that the leading and next-to-leading order terms of the operator product expansion (OPE) give rise to the Tomozawa-Weinberg and sigma terms, respectively in the pion-nucleon and kaon-nucleon scattering lengths. We discuss phenomenological contributions which should be added to the experimental scattering lengths to be compared with the theoretical calculation by the OPE: we estimate the Lambda(1405) contribution in the kaon-nucleon channel by using the effective coupling strength determined by the analysis of the scattering data. We also estimate the continuum contribution above the threshold in the pion-nucleon channel by using the nonlinear sigma model. It turns out that the results of the QCD sum rule for the pion-nucleon scattering lengths are consistent with those of the low energy theorem and therefore with experiments and those for the kaon-nucleon scattering lengths differ from the results of naive partial conservation of axial-vector current-plus-current-algebra approach by the contribution from Lambda(1405).
  • Y Kondo, O Morimatsu, Y Nishino
    PHYSICAL REVIEW C 53 4 1927 - 1935 1996年04月 [査読有り][通常論文]
     
    The pion-nucleon and kaon-nucleon scattering lengths are studied in the QCD sum rule. We show that the leading and next-to-leading order terms of the operator product expansion (OPE) give rise to the Tomozawa-Weinberg and sigma terms, respectively in the pion-nucleon and kaon-nucleon scattering lengths. We discuss phenomenological contributions which should be added to the experimental scattering lengths to be compared with the theoretical calculation by the OPE: we estimate the Lambda(1405) contribution in the kaon-nucleon channel by using the effective coupling strength determined by the analysis of the scattering data. We also estimate the continuum contribution above the threshold in the pion-nucleon channel by using the nonlinear sigma model. It turns out that the results of the QCD sum rule for the pion-nucleon scattering lengths are consistent with those of the low energy theorem and therefore with experiments and those for the kaon-nucleon scattering lengths differ from the results of naive partial conservation of axial-vector current-plus-current-algebra approach by the contribution from Lambda(1405).
  • Nishino, Y
    International Journal of Modern Physics E-Nuclear Physics 5 1 121 - 129 1996年03月 [査読有り][通常論文]
  • Y Nishino
    INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS 5 1 121 - 129 1996年03月 [査読有り][通常論文]
     
    We calculate the second moment M(2)(S) of the flavor-singlet structure function F-2(S) for the pion and the kaon in the framework of the QCD sum rule, and investigate how the results depend on their flavor structure (quark contents). Our calculations give similar values of M(2)(S) for these two mesons as a result of the cancellation among several non-small factors.

書籍

  • • Synchrotron Radiation and Structural Proteomics (Pan Stanford Series on Nanobiotechnology Vol.3)
    Pan Stanford Publishing 2011年
  • 放射光が解き明かす驚異のナノ世界 -魔法の光が拓く物質世界の可能性-
    講談社 2011年

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  • ナノイメージング特論
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 情報科学研究科
    キーワード : ナノイメージング、X線計測、物質とX線との相互作用、X線源
  • ナノイメージング特論
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 情報科学院
    キーワード : ナノイメージング、X線計測、物質とX線との相互作用、X線源
  • ナノイメージング特論
    開講年度 : 2019年
    課程区分 : 博士後期課程
    開講学部 : 情報科学研究科
    キーワード : ナノイメージング、X線計測、物質とX線との相互作用、X線源
  • ナノイメージング特論
    開講年度 : 2019年
    課程区分 : 博士後期課程
    開講学部 : 情報科学院
    キーワード : ナノイメージング、X線計測、物質とX線との相互作用、X線源
  • ナノ工学基礎
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 波動の重ね合わせ、干渉、回折、偏光、フーリエ光学、コヒーレンス、ナノ工学、次元解析
  • 応用光学Ⅱ
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 波動の重ね合わせ、干渉、回折、偏光、フーリエ光学、コヒーレンス、ナノ工学、次元解析

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  • 2015年10月1日 - 2017年9月30日 電子科学研究所附属グリーンナノテクノロジー研究センター長


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