基本情報

所属

• 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

職名

• 准教授

学位

• 博士(理学)（2016年03月 東京大学）

科研費研究者番号

• 50784617

ORCID ID

•  https://orcid.org/0000-0003-2010-3966

J-Global ID

• 202101010342922022

研究キーワード

• 酸化物薄膜   

担当教育組織

•  修士課程　情報科学院
•  博士課程　情報科学院

職歴

• 2021年04月 - 現在 北海道大学 電子科学研究所 准教授
• 2021年10月 - 2024年03月 JST さきがけ (兼任)
• 2019年01月 - 2021年03月 東京大学 大学院理学系研究科 助教
• 2018年01月 - 2018年12月 東京大学 大学院理学系研究科 特任助教
• 2016年04月 - 2017年12月 東京工業大学 フロンティア材料研究所 博士研究員
• 2014年04月 - 2016年03月 独立行政法人日本学術振興会 特別研究員

学歴

• 2013年04月 - 2016年03月   東京大学   大学院理学系研究科   化学専攻
• 2011年04月 - 2013年03月   東京大学   大学院理学系研究科   化学専攻
• 2007年04月 - 2011年03月   東京大学   理学部   化学科

研究活動情報

論文

• Ferroelectricity, High Permittivity, and Tunability in Millimeter-Size Crack-Free Ba1–xSrxTiO3 Flexible Epitaxial Sheets

  Rui Yu, Lizhikun Gong, Hiromichi Ohta, Tsukasa Katayama

  ACS Applied Electronic Materials 2023年09月26日
• Atomic Layer Deposition of HfO₂ Films Using Tetrakis(1-(N,N-dimethylamino)-2-propoxy)hafnium [Hf(dmap)₄] for Advanced Gate Dielectrics Applications

  Akihiro Nishida, Tsukasa Katayama, Yasutaka Matsuo

  ACS Applied Nano Materials 2023年09月15日
• Anisotropic proton conduction in double-perovskite GdBaCo2O5.5

  Tsukasa Katayama, Kento Magara, Akira Chikamatsu, Tetsuya Hasegawa

  Applied Physics Letters 2023年07月03日
• Solid phase epitaxy of perpendicular magnetic BaFe₁₂O₁₉ flexible sheets on a mica substrate

  Tsukasa Katayama, Shishin Mo, Akira Chikamatsu, Tetsuya Hasegawa

  Japanese Journal of Applied Physics 62 6 065505 - 065505 2023年06月01日 

  Abstract Epitaxial M-type BaFe₁₂O₁₉ flexible sheets, exhibiting RT perpendicular magnetization, were synthesized on mica substrates through the solid phase epitaxy method. The [110] and [001] directions of the BaFe₁₂O₁₉ layer were parallel to the [010] and [001] directions of the mica, respectively. In the synthesis process, amorphous BaFe₁₂O₁₉ films were firstly prepared on Al₂O₃-buffered mica (001) substrates and then annealed at 800 °C–900 °C in air for single crystallization. During optimization of the synthesis, we found that preparation of the buffer layer and controlling annealing temperature are important for obtaining the epitaxial sheet. The sheets exhibited perpendicular ferrimagnetism with large saturated magnetization (60 Am² kg⁻¹) and magnetic anisotropy coefficient (2.1 × 10⁵ J m⁻³) at 300 K, together with flexibility.
• Half-Metallicity and Magnetic Anisotropy in Double-Perovskite GdBaCo₂O₆ Films Prepared via Topotactic Oxidation

  Tsukasa Katayama, Shishin Mo, Akira Chikamatsu, Yuji Kurauchi, Hiroshi Kumigashira, Tetsuya Hasegawa

  Chemistry of Materials 2023年01月18日
• Atomic layer deposition of Y₂O₃ films using a novel liquid homoleptic yttrium precursor tris(sec-butylcyclopentadienyl)yttrium [Y(^sBuCp)₃] and water

  Akihiro Nishida, Tsukasa Katayama, Yasutaka Matsuo

  RSC Advances 13 39 27255 - 27261 2023年 [査読有り]
   

  Atomic layer deposition of Y₂O₃ films was demonstrated using a novel liquid homoleptic yttrium precursor Y(^sBuCp)₃ and water. The deposited Y₂O₃ films exhibit high purity, high crystallinity, a smooth surface, and high electronic performance.
• Grain engineered polar-axis-oriented epitaxial Mn₂Mo₃O₈ films with enhanced magnetic transition temperature

  Shishin Mo, Tsukasa Katayama, Akira Chikamatsu, Tetsuya Hasegawa

  Journal of Materials Chemistry C 2023年 

  Magnetic transition temperature of polar-axis-oriented Mn₂Mo₃O₈ epitaxial films was enhanced by grain engineering.
• Synthesis and transparent conductivity of crack-free La:BaSnO₃ epitaxial flexible sheets

  Lizhikun Gong, Rui Yu, Hiromichi Ohta, Tsukasa Katayama

  Dalton Transactions 2023年 

  La-doped BaSnO₃ (LBSO), which exhibits both high electron mobility and visible-light transparency, is a promising transparent electrode/transistor material that does not require expensive elements such as indium.
• Significant Suppression of Cracks in Freestanding Perovskite Oxide Flexible Sheets Using a Capping Oxide Layer

  Lizhikun Gong, Mian Wei, Rui Yu, Hiromichi Ohta, Tsukasa Katayama

  ACS Nano 2022年12月27日
• Hexagonal RFeO3 (R = Dy, Er, and Lu) Films Grown on Glass Substrates with Both Magnetic and Ferroelectric Orders

  Binjie Chen, Tsukasa Katayama

  ACS Applied Electronic Materials 2022年12月20日
• Photo-induced antiferromagnetic-ferromagnetic and spin-state transition in a double-perovskite cobalt oxide thin film

  Yujun Zhang, Tsukasa Katayama, Akira Chikamatsu, Christian Schü{\ss}ler-Langeheine, Niko Pontius, Yasuyuki Hirata, Kou Takubo, Kohei Yamagami, Keisuke Ikeda, Kohei Yamamoto, Tetsuya Hasegawa, Hiroki Wadati

  Communications Physics 5 1 2022年12月 

  AbstractInvestigation of ultrafast dynamic behaviors can provide novel insights about the coupling mechanisms among multiple degrees of freedom in condensed matters, such as lattice, magnetism and electronic structure. Here we investigate both the ferromagnetic (FM) and antiferromagnetic (AFM) dynamics of a strongly correlated oxide system, GdBaCo2O5.5 thin film by time-resolved x-ray magnetic circular dichroism in reflectivity (XMCDR) and resonant magnetic x-ray diffraction (RMXD). A photo-induced AFM-FM transition characterized by an increase of the transient XMCDR (sensitive to FM order) beyond the unpumped value and a decay of RMXD (sensitive to AFM order) was observed. The photon-energy dependence of the transient XMCDR and reflectivity could be interpreted as a concomitant photo-induced spin-state transition (SST). The AFM-FM transition and SST couple with each other in the time domain, resulting in unusual dynamic behaviors of the magnetism.
• Epitaxial growth of hexagonal GdFeO3 thin films with magnetic order by pulsed laser deposition

  Jun Kasahara, Tsukasa Katayama, Akira Chikamatsu, Yosuke Hamasaki, Tetsuya Hasegawa

  Thin Solid Films 757 139409 - 139409 2022年09月
• Ferroelectric and Magnetic Properties of Hexagonal ErFeO₃ Epitaxial Films

  Binjie Chen, Hiromichi Ohta, Tsukasa Katayama

  ACS Applied Electronic Materials 2022年08月23日
• Ionic order and magnetic properties of double-perovskite GdBaCo₂O_5.5 films on SrTiO₃ substrates

  Tsukasa Katayama, Akira Chikamatsu, Tetsuya Hasegawa

  Journal of the Ceramic Society of Japan 130 7 429 - 431 2022年07月01日
• Enhancement of room-temperature magnetization in GaFeO₃-type single crystals by Al and Sc doping

  Ling Wang, Tsukasa Katayama, Chaoyue Wang, Qin Li, Yun Shi, Yuqiang Fang, Fuqiang Huang, Yinghao Zhu, Hai-feng Li, Shintaro Yasui, Xintang Huang, Jianding Yu

  AIP Advances 12 6 065015 - 065015 2022年06月01日 

  GaFeO₃-type oxides are promising multiferroic materials due to the coexistence of spontaneous magnetization and ferroelectric polarization properties at room temperature. As these ferroic properties feature a large anisotropy, single crystals are required. However, the magnetization of GaFeO₃-type single crystals remains low at room temperature. In this study, we largely enhanced the magnetization at room temperature of GaFeO₃-type single crystals by increasing the Fe content and co-doping Sc³⁺ and Al³⁺. Single crystals of Al _xSc_{0.1− x}Ga_0.6Fe_1.3O₃ ( x = 0.01–0.04) were prepared using the optical floating-zone method. The single crystals were rod-shaped, with a diameter and length of ∼6 mm and 7 cm, respectively. X-ray diffraction measurements confirmed the ferroelectric polarization of the crystals. In addition, they exhibited room-temperature ferrimagnetism, with Curie temperature in the range of 326–338 K; the crystals exhibit magnetic anisotropy along the a-axis. The magnetization of the single crystal at 300 K and 0.3 kOe was 13 emu g⁻¹, which is over ten times larger than those of previously reported single crystals with GaFeO₃-type crystal structure.
• Crystal structure and electronic property modification of Ca2RuO4 thin films via fluorine doping

  Shota Fukuma, Akira Chikamatsu, Tsukasa Katayama, Takahiro Maruyama, Keiichi Yanagisawa, Koji Kimoto, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Yasushi Hirose, Tetsuya Hasegawa

  Physical Review Materials 6 3 2022年03月23日 

  Layered ruthenium oxyfluorides have various crystal structures and Ru oxidation states and exhibit unique physical properties. While various layered ruthenates have reportedly been topochemically fluorinated with Sr as A sites, investigation of the fluorination of layered ruthenates containing smaller Ca ions is lacking. In this paper, we fabricated phase-pure and single-crystalline thin films of Ca2RuO2.5F2 on LaSrAlO4 (001) substrates via topochemical fluorination of the Ca2RuO4 precursor using polyvinylidene fluoride. The obtained fluorinated thin films had a chemical composition of Ca2RuO2.5F2 with the Ru3+ state, as determined by energy-dispersive x-ray spectroscopy and x-ray photoemission spectroscopy, whereas the film prepared via Sr2Ru4+O4 fluorination had a composition of (Sr2Ru4+O3F2). Scanning transmission electron microscopy revealed that Ca2RuO2.5F2 has only 1 F- site in CaO rock-salt blocks, whereas Sr2RuO3F2 has two inequivalent F- sites in the SrO layers. The Ca2RuO2.5F2 film was insulating, with a resistivity (rho) of 8.6 x 10(-2) Omega cm at 300 K. Moreover, the temperature behavior of rho was well described by the two-dimensional variable range hopping model. These results demonstrate that local distortion is an important factor that governs the topochemical fluorination of ruthenates and affects the crystal and electronic structures of the reactants.
• Negative magnetoresistance in different nitrogen content EuNbO_3−xN_x single-crystalline thin films

  Takahiro Maruyama, Yasushi Hirose, Tsukasa Katayama, Yuki Sugisawa, Daiichiro Sekiba, Tetsuya Hasegawa, Akira Chikamatsu

  Journal of Materials Chemistry C 2022年 

  In EuNbO_3−xN_x single-crystalline thin films, the transport properties gradually changed from metallic to semiconducting and the negative magnetoresistance at 2 K increased from 15% to 98% with x.
• Antiferroelectric-to-ferroelectric phase transition in hexagonal rare-earth iron oxides

  Binjie Chen, Tetsuya Hasegawa, Hiromichi Ohta, Tsukasa Katayama

  Journal of Materials Chemistry C 10 14 5621 - 5626 2022年
• Improvement of electric insulation in dielectric layered perovskite nickelate films via fluorination

  Takuma Nishimura, Tsukasa Katayama, Shishin Mo, Akira Chikamatsu, Tetsuya Hasegawa

  Journal of Materials Chemistry C 2022年 

  Epitaxial films of La_3/2Sr_1/2NiO_xF_y with a wide range of fluorine content (y), 0.4–3, were prepared. The fluorinated film exhibited high electric insulation due to the large and random bond distortions provided by the fluorination.
• Ferroelectric and magnetic properties in ε-Fe2O3 epitaxial film

  Yosuke Hamasaki, Shintaro Yasui, Tsukasa Katayama, Takanori Kiguchi, Shinya Sawai, Mitsuru Itoh

  Applied Physics Letters 119 18 182904 - 182904 2021年11月01日
• Epitaxial-Strain-Induced Spontaneous Magnetization in Polar Mn2Mo3O8

  Shishin Mo, Tsukasa Katayama, Akira Chikamatsu, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Tetsuya Hasegawa

  Chemistry of Materials 33 19 7713 - 7718 2021年10月12日
• Single-Crystal Synthesis of ε-Fe2O3-Type Oxides Exhibiting Room-Temperature Ferrimagnetism and Ferroelectric Polarization

  Yang Zhang, Hui Wang, Koki Tachiyama, Tsukasa Katayama, Yinghao Zhu, Si Wu, Hai-Feng Li, Jinghong Fang, Qin Li, Yun Shi, Ling Wang, Zhengqian Fu, Fangfang Xu, Jianding Yu, Shintaro Yasui, Mitsuru Itoh

  Crystal Growth & Design 2021年07月29日
• Ionic Order Engineering in Double-Perovskite Cobaltite

  Tsukasa Katayama, Akira Chikamatsu, Yujun Zhang, Shintaro Yasui, Hiroki Wadati, Tetsuya Hasegawa

  Chemistry of Materials 33 14 5675 - 5680 2021年07月27日 

  Double-perovskite GdBaCo2O5.5 (GBCO) exhibits various fascinating features, including temperature- and magnetic-field-induced ferromagnetic to antiferromagnetic phase transition associated with the two ionic orders: an A-site Gd/Ba order along the c-axis, and an octahedral CoO6/pyramidal CoO5 order along the b-axis. However, the fine control of ionic orders remains a challenging issue. Herein, we demonstrate the engineering of ionic orders in GBCO films through appropriate selection of substrates. Specifically, we prepared four kinds of films comprising only the Gd/Ba order [on SrTiO3(001)], only the CoO6/CoO5 order [on LaSrGaO4(001)], and both the Gd/Ba and CoO6/CoO5 orders [on NdGaO3(110) and LaSrAlO4(001) (LSAO)]. In addition to the selective ionic orders through substrate selection, the GBCO film on LSAO also contained multiple domains with domain boundaries of [CoOx]-[CoOy] stacking. Magnetic, magnetoresistance, and resonant X-ray magnetic diffraction measurements revealed that the magnetic properties of the above GBCO films were widely modulated. With the ionic order control of the GBCO film, different magnetic phase transition behaviors and magnetic anisotropy switching from the in-plane to perpendicular direction were observed.
• Synthesis and magnetism of MoCo2O4 spinel thin films

  Tsukasa Katayama, Shishin Mo, Yuji Kurauchi, Akira Chikamatsu, Tetsuya Hasegawa

  Thin Solid Films 728 138696 - 138696 2021年06月
• Room-Temperature Antiferroelectricity in Multiferroic Hexagonal Rare-Earth Ferrites

  Jun Kasahara, Tsukasa Katayama, Shishin Mo, Akira Chikamatsu, Yosuke Hamasaki, Shintaro Yasui, Mitsuru Itoh, Tetsuya Hasegawa

  ACS Applied Materials & Interfaces 13 3 4230 - 4235 2021年01月27日 

  The antiferroelectric (AFE) phase, in which nonpolar and polar states are switchable by an electric field, is a recent discovery in promising multiferroics of hexagonal rare-earth manganites (ferrites), h-RMn(Fe)O3. However, this phase has so far only been observed at 60-160 K, which restricts key investigations into the microstructures and magnetoelectric behaviors. Herein, we report the successful expansion of the AFE temperature range (10-300 K) by preparing h-DyFeO3 films through epitaxial stabilization. Room-temperature scanning transmission electron microscopy reveals that the AFE phase originates from a nanomosaic structure comprising AFE P3̅c1 and ferroelectric P63cm domains with small domain sizes of 1-10 nm. The nanomosaic structure is stabilized by a low c/a ratio derived from the large ionic radius of Dy3+. Furthermore, weak ferromagnetism and magnetocapacitance behaviors are observed. Below 10 K, the film exhibits an M-shaped magnetocapacitance versus magnetic field curve, indicating unusual magnetoelectric coupling in the AFE phase.
• Large Polarization Switching and High-Temperature Magnetoelectric Coupling in Multiferroic GaFeO3 Systems

  Hui Wang, Yang Zhang, Koki Tachiyama, Zhaoyang Xia, Jinghong Fang, Qin Li, Guofeng Cheng, Yun Shi, Ji, ing Yu, Tsukasa Katayama, Shintaro Yasui, Mitsuru Itoh

  Inorganic Chemistry 60 1 225 - 230 2021年01月04日 

  GaFeO3-type iron oxides are promising multiferroics due to the coexistence of large spontaneous magnetization and polarization near room temperature. However, the high leakage current and difficulties associated with synthesizing single crystals E-induced make it difficult to achieve two important features in the system: a P switching large ferroelectric polarization switching and magnetoelectric coupling at a high-temperature region. Herein, we report successful achievement of these features by preparing high-quality Sc-doped GaFeO3 single crystals (ScxGa1-x/2Fe1-x/2O3 with x= 0-0.3) using the floating zone method. The x >= 0.05 crystals exhibit a leakage current 10(4) times lower than the x = 0 crystals, highlighting the importance of Sc doping. Because of the reduced leakage current, the Sc-doped crystals exhibit large ferroelectric polarization switching along the c-axis with a remanent polarization of 22-25 mu C/cm(2), which is close to the theoretically predicted polarization value of 25-28 mu C/cm(2). In addition, the Sc-doped crystals exhibit ferrimagnetism with magnetic anisotropy along the a-axis. Furthermore, a magnetic-field-induced modulation of polarization is observed in the x = 0.15 crystal even at a relatively high temperature, i.e., 100 K.
• Investigation of the electronic states of A-site layer-ordered double perovskite YBaCo2Ox (x = 5.3 and 6) thin films by x-ray spectroscopy

  Akira Chikamatsu, Tsukasa Katayama, Takahiro Maruyama, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Hiroki Wadati, Tetsuya Hasegawa

  Applied Physics Letters 118 1 012401 - 012401 2021年01月04日 

  In this study, the electronic structures of A-site layer-ordered double perovskite YBaCo2O6 and YBaCo2O5.3 epitaxial thin films were investigated by x-ray photoemission spectroscopy (PES), x-ray absorption spectroscopy (XAS), and x-ray magnetic circular dichroism (XMCD) measurements. The valence band PES spectrum of the YBaCo2O6 thin film exhibited a finite density of states (DOS) at the Fermi energy (EF), while that of the YBaCo2O5.3 thin film exhibited no DOS at EF, corresponding well with the metallic and insulating transport properties, respectively. The Co L-edge XAS measurements revealed that the Co ions in YBaCo2O6 are in a mixed valence state of high-spin (HS) Co3+ (50%) and intermediate spin (IS) Co4+ (50%), while HS Co3+ (80%) and HS Co2+ (20%) coexist in YBaCo2O5.3. The XMCD measurements led to the conclusion that both HS Co3+ and IS Co4+ contribute to the ferromagnetism of YBaCo2O6.
• Simple Method to Obtain Large‐Size Single‐Crystalline Oxide Sheets

  Ke Gu, Tsukasa Katayama, Shintaro Yasui, Akira Chikamatsu, Sou Yasuhara, Mitsuru Itoh, Tetsuya Hasegawa

  Advanced Functional Materials 30 28 2001236 - 2001236 2020年07月25日 

  Synthetic techniques to prepare large-size, flexible, and high-quality single-crystalline sheets of transition metal oxides are crucial to developing low-energy consumption devices. One promising way is a lift-off and transfer technique using a heterostructure of polymer supporting oxide and Sr3Al2O6 (SAO) layers grown on a single-crystalline substrate. By removing the water-soluble SAO and the supporting layers, the oxide sheet is obtained. Although some ferroelectric flexible sheets are prepared by this method, a simpler method for obtaining large-size sheets is required. Herein, a lift-off and transfer method is proposed without a supporting layer. With this simple method, single-crystalline SrRuO3 and BaTiO3 flexible sheets with a lateral size of a few millimeters are successfully prepared. The SrRuO3 sheet exhibits high crystallinity and conductivity. Meanwhile, the ferroelectricity of the BaTiO3 sheet is successfully observed via polarization hysteresis loop measurements. In addition to the simplicity, this method has low costs and the substrate is reusable. Accordingly, the proposed method could enhance the development of various kinds of large-size functional oxide sheets.
• Modulating the Structure and Magnetic Properties of ε-Fe2O3 Nanoparticles via Electrochemical Li+ Insertion

  Tsukasa Katayama

  Inorganic Chemistry 59 7 4357 - 4365 2020年04月06日 

  epsilon-Fe2O3, a metastable phase of iron oxide, is widely known as a room-temperature multiferroic material or as a superhard magnet. Element substitution into epsilon-Fe2O3 has been reported in the literature; however, the substituted ions have a strong site preference depending on their ionic radii and valence. In this study, in order to characterize the crystal structure and magnetic properties of epsilon-Fe2O3 in the Fe2+/Fe3+ coexisting states, Li+ was electrochemically inserted into epsilon-Fe2O3 to reduce Fe3+. The discharge and charge of Li+ into/from epsilon-Fe2O3 revealed that Li+ insertion was successful. X-ray magnetic circular dichroism results indicated that the reduced Fe did not exhibit site preference. Increasing the Li+ content in epsilon-Fe2O3 resulted in decreased saturation magnetization and irregular variation of the coercive field. We present a comprehensive discussion of how magnetic properties are modified with increasing Li+ content using transmission electron microscopy images and considering the L+ diffusion coefficient. The results suggest that inserting L+ into crystalline epsilon-Fe2O3 is a useful tool for characterizing crystal structure, lithiation limit, and magnetic properties in the coexistence of Fe2+/Fe3+.
• Redox-based multilevel resistive switching in AlFeO3 thin-film heterostructures

  Tsukasa Katayama

  ACS Applied Electronic Materials 2 4 1065 - 1073 2020年03月29日
• 六方晶GdFeO₃マルチフェロイック薄膜の合成

  笠原 淳, 片山 司, 毛 司辰, 近松 彰, 安井 伸太郎, 伊藤 満, 長谷川 哲也

  応用物理学会学術講演会講演予稿集 2020.1 1354 - 1354 公益社団法人 応用物理学会 2020年02月28日
• Electronic properties of perovskite strontium chromium oxyfluoride epitaxial thin films fabricated via low-temperature topotactic reaction

  Akira Chikamatsu, Takahiro Maruyama, Tsukasa Katayama, Yu Su, Yoshihiro Tsujimoto, Kazunari Yamaura, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Tetsuya Hasegawa

  Physical Review Materials 4 2 2020年02月18日 

  Perovskite chromium oxyfluoride SrCrO2.6F0.4 epitaxial thin films were fabricated via low-temperature topotactic fluorination of SrCrO2.8 precursor with polyvinylidene fluoride as a fluorine source. The obtained SrCrO2.6F0.4 thin film had a different chemical composition than that of bulk polycrystalline SrCrO2.8F0.2, possibly due to the higher reactivity of such thin film. Both the precursor and fluorinated thin films containing Cr3.6+ exhibited insulating behavior with band gaps of ∼0.6 eV, in contrast to metallic SrCrO3 with Cr4+ at 300 K. The experimentally observed valence and conduction bands of the SrCrO2.8, SrCrO3, and SrCrO2.6F0.4 thin films suggested that the spectral weight transfer from the coherent part to the incoherent part with the reduction of Cr valences was caused by strong electron correlation effects. This study offers a fundamental understanding of the fluorine doping effects on a crystalline structure and the correlated electronic performance of chromium oxides.
• Switchable third ScFeO3 polar ferromagnet with YMnO3-type structure

  Yosuke Hamasaki, Tsukasa Katayama, Shintaro Yasui, Takahisa Shiraishi, Akihiro Akama, Takanori Kiguchi, Tomoyasu Taniyama, Mitsuru Itoh

  Journal of Materials Chemistry C 8 13 4447 - 4452 2020年 

  We prepared a third ScFeO₃ polar ferromagnet with YMnO₃-type structure using a heteroepitaxial film technique and characterized its physical properties.

• Influence of fluorination on electronic states and electron transport properties of Sr2IrO4 thin films

  Takahiro Maruyama, Akira Chikamatsu, Tsukasa Katayama, Kenta Kuramochi, Hiraku Ogino, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Tetsuya Hasegawa

  Journal of Materials Chemistry C 8 24 8268 - 8274 2020年 

  We fabricated layered-perovskite Sr2IrO4-xF2x thin films by combining pulsed-laser deposition with topotactic fluorination and investigated their structures, electronic states, and electron transport properties. In the fluorination process, the insertion of fluorine into SrO rock-salt layers and the partial removal of oxygen occurred simultaneously while keeping Ir4+. The fluorine amount was evaluated to be 2x ≈ 3, which was much larger than the bulk value. Optical and photoemission measurements revealed that the effective total angular momentum Jeff = 3/2 is stabilized upon fluorination owing to the large electronegativity of fluorine. The Sr2IrO4-xF2x film exhibited a semiconducting behavior described by Efros-Shklovskii variable-range hopping with ρ(T) ≈ T-1/2. These results will be useful for modifying electronic states by anion doping to explore unprecedented physical properties in Ruddlesden-Popper-type iridates. This journal is
• Investigation of ferrimagnetism and ferroelectricity in AlxFe2−xO3 thin films

  Badari Narayana Rao, Shintaro Yasui, Tsukasa Katayama, Ayako Taguchi, Hiroki Moriwake, Yosuke Hamasaki, Mitsuru Itoh

  Journal of Materials Chemistry C 8 2 706 - 714 2020年 

  AlxFe2-xO3 (x-AFO) thin films, belonging to the kappa-Al2O3 family, are interesting because they show room temperature ferrimagnetism and have a polar crystal structure. These types of materials are being studied to observe simultaneous ferrimagnetism and ferroelectricity, and the possibility of coupling between the two. However, it is difficult to realise ferroelectric properties at room temperature, due to the low resistivity of the films. In this work, we have optimized the synthesis conditions to obtain x-AFO (0.5 <= x <= 1) thin films with high resistance. While magnetic measurements confirmed room temperature ferrimagnetism of the films, the maximum magnetization was observed for the composition x = 0.8. In addition, the Curie temperature was found to be influenced by oxygen pressure during deposition. Ferroelectric measurements on the films showed small remnant polarization (similar to 0.5-2 mu C cm(-2)). In contrast, the predicted polarization from first principles calculations was calculated to be between 21 and 26 mu C cm(-2). The analysis also suggested that ferroelectric domain-switching occurs through shearing of in-plane oxygen layers. The presence of multiple in-plane domains, which oppose polarization switching of adjacent domains, is suggested to be the cause of the small observed polarization. The magnetocapacitance measurements showed weak magnetic coupling with the capacitance.
• Two-Dimensional Fluorine Distribution in a Heavily Distorted Perovskite Nickel Oxyfluoride Revealed by First-Principles Calculation

  Yuji Kurauchi, Tsukasa Katayama, Akira Chikamatsu, Tetsuya Hasegawa

  The Journal of Physical Chemistry C 123 51 31190 - 31195 2019年12月26日
• Theoretical Investigation of the Role of the Nitride Ion in the Magnetism of Oxynitride MnTaO2N

  Shishin Mo, Yuji Kurauchi, Tsukasa Katayama, Yasushi Hirose, Tetsuya Hasegawa

  The Journal of Physical Chemistry C 123 41 25379 - 25384 2019年10月17日
• Ferroelectric and ferrimagnetic properties of ε-RhxFe2−xO3 thin films

  Tsukasa Katayama

  Journal of the Ceramic Society of Japan 127 7 474 - 477 2019年07月01日 

  RhxFe2-xO3 solid-solution epitaxial thin films were prepared by pulsed laser deposition. The ferroelectricity of Rh0.15Fe1.85O3 thin film was presented by the result of piezoelectric force microscopy phase and amplitude loops measured at room temperature. Ferrimagnetism at room temperature is confirmed by the magnetic hysteresis loop. The coercive field of Rh0.15Fe1.85O3 thin film at 5K is 12 kOe, which is larger than that of epsilon-Fe2O3. Rh0.15Fe1.85O3 is confirmed to be a room temperature multiferroic material. (C) 2019 The Ceramic Society of Japan. All rights reserved.
• Improved crystalline quality and electric conductivity in infinite-layer SrFeO2 films through Sm substitution

  Tsukasa Katayama, Akira Chikamatsu, Hiroshi Kumigashira, Tetsuya Hasegawa

  Applied Physics Letters 2019年06月10日
• p-Type Conductivity and Room-Temperature Ferrimagnetism in Spinel MoFe2O4 Epitaxial Thin Film

  Tsukasa Katayama, Yuji Kurauchi, Shishin Mo, Ke Gu, Akira Chikamatsu, Lyaysan Galiullina, Tetsuya Hasegawa

  Crystal Growth & Design 19 2 902 - 906 2019年02月06日
• Selective fluorination of perovskite iron oxide/ruthenium oxide heterostructures via a topotactic reaction

  Akira Chikamatsu, Yusuke Suzuki, Takahiro Maruyama, Tomoya Onozuka, Tsukasa Katayama, Daisuke Ogawa, Tetsuya Hasegawa

  Chemical Communications 2019年
• Fabrication and Characterization of Multiferroic Al0.5Fe1.5O3 Epitaxial Thin Films

  Tsukasa Katayama

  MRS Advances 4 9 539 - 544 2019年 

  ABSTRACTSingle-phase multiferroic materials have attracted considerable attention among scientists, due to the strong drive in industry towards device miniaturization, addition of new functionalities, etc. Currently, most of the discovered materials have at-least one ferroic order active only at low temperatures, thereby hindering their induction into practical devices. κ-Al2O3-type AlxFe2-xO3 (x-AFO) oxides belong to a new class of metastable multiferroic compounds (space group: Pna21), with relatively high Curie temperatures. The current work investigates the effect of thin film deposition conditions on the ferroelectric and ferrimagnetic properties of Al0.5Fe1.5O3 (0.5-AFO). Substrate temperature and oxygen partial pressure during deposition were found to be the critical parameters in obtaining high quality films. Optimizing the deposition conditions of 0.5-AFO enabled observation of both ferroelectricity and ferrimagnetism at room temperature.
• Magnetic properties of Single Crystal GaFeO3

  Tsukasa Katayama

  MRS Advances 4 1 61 - 66 2019年 

  Abstractκ-Al2O3-type GaFeO3 is a promising multiferroic material due to the coexistence of a large spontaneous magnetization and polarization near room temperature. In the current study, we present the magnetic properties of single crystalline GaFeO3 and compare it with that of ε-Fe2O3. Magnetic measurements revealed that spontaneous magnetization appears below 540 K in two steps, similar to that reported for ε−Fe2O3. Partial magnetic ordering takes place at 540 K (TN1), with Fe3+ ions in two distorted octahedral sites ordering antiparallel to one another. Upon further cooling at 200 K (TN2), the remaining Fe3+ ions in regular octahedra and tetrahedra order antiparallel to one another. Substitution of Ga for Fe in ε-Fe2O3 leads to a decrease in TN1 and TN2 from 850 to 540 K and from 480 to 200 K, respectively, caused by a dilution of magnetic Fe by nonmagnetic Ga and preferential site occupation of Ga.
• Reactive solid phase epitaxy of layered aurivillius-type oxyfluorides Bi2TiO4F2 using polyvinylidene fluoride

  Tsukasa Katayama, Shishin Mo, Takahiro Maruyama, Akira Chikamatsu, Tetsuya Hasegawa

  Dalton Transactions 2019年
• Epitaxial Growth of Orthorhombic GaFeO₃ Thin Films on SrTiO₃ (111) Substrates by Simple Sol-Gel Method.

  Zhang, Minghui, Yasui, Shintaro, Katayama, Tsukasa, Rao, Badari Narayana, Wen, Haiqin, Pan, Xiuhong, Tang, Meibo, Ai, Fei, Itoh, Mitsuru

  Materials (Basel, Switzerland) 12 2 2019年 

  A Sol-gel method assisted with spin-coating has been successfully used to grow orthorhombic GaFeO₃ epitaxial films on SrTiO₃ (111) substrates for the first time. The film with Pna2₁ crystal structure has been grown along the c-axis. The rocking curve of (004) reflection shows that the Full-Width at Half-Maximum (FWHM) value could be determined to be 0.230°, indicating good single crystallinity and high quality. X-ray Φ scan reveals a three-fold symmetry of the substrate and a six-fold symmetry of the film, respectively. The in-plane domains rotate 60° from each other in the film. Uniform film with dense structure, columnar grains with similar grain size was obtained. The thickness of the film was evaluated to be ~170 nm. The roughness value (RMS) measured by AFM was 4.5 nm, revealing a flat film. The in-plane Magnetization versus Magnetic field (M-H) curve at 5 K performs a typical ferri- or ferromagnetic hysteresis loop with a saturated magnetization (Ms) value of 136 emu/cm³. The Curie temperature could be determined to be 174 K. Compared to Pulsed Laser Deposition (PLD), the sol-gel method can prepare large area films with low cost. These new films show promising applications in multiferroic devices.
• 単結晶SrRuO₃シートの合成

  Gu Ke, 片山 司, 安井 伸太郎, 近松 彰, 伊藤 満, 長谷川 哲也

  応用物理学会学術講演会講演予稿集 2018.2 1505 - 1505 公益社団法人 応用物理学会 2018年09月05日
• Ferroelectric and Magnetic Properties in Room-Temperature Multiferroic Ga x Fe2− x O3 Epitaxial Thin Films

  Tsukasa Katayama, Shintaro Yasui, Yosuke Hamasaki, Takahisa Shiraishi, Akihiro Akama, Takenori Kiguchi, Mitsuru Itoh

  Advanced Functional Materials 1704789 - 1704789 2018年01月27日
• Fabrication of Fluorite-Type Fluoride Ba0.5Bi0.5F2.5 Thin Films by Fluorination of Perovskite BaBiO3 Precursors with Poly(vinylidene fluoride)

  Chikamatsu, Akira, Kawahara, Keisuke, Shiina, Takaaki, Onozuka, Tomoya, Katayama, Tsukasa, Hasegawa, Tetsuya

  Acs Omega 3 10 2018年
• Effect of Cr substitution on ferrimagnetic and ferroelectric properties of GaFeO3 epitaxial thin films

  Katayama, Tsukasa, Osakabe, Takuya, Yasui, Shintaro, Hamasaki, Yosuke, Rao, Badari Narayana, Zhang, Minghui, Itoh, Mitsuru

  Applied Physics Letters 113 16 162901 - 162901 2018年
• Ferromagnetism with strong magnetocrystalline anisotropy in A-site ordered perovskite YBaCo2O6 epitaxial thin films prepared via wet-chemical topotactic oxidation

  Katayama, Tsukasa, Chikamatsu, Akira, Hirose, Yasushi, Minohara, Makoto, Kumigashira, Hiroshi, Harayama, Isao, Sekiba, Daiichiro, Hasegawa, Tetsuya

  Journal of Materials Chemistry C 6 13 3445 - 3450 2018年 

  A-site cation-ordered perovskite cobaltite, RBaCo2Ox (R = rare earth element), exhibits fascinating physical properties, such as spin-state ordering and high oxygen conductivity, because of the large tetragonal distortion of the Co orbital. However, the distorted coordination geometry prefers oxygen vacancies, resulting in a difficulty in obtaining the stoichiometric phase (x = 6). For example, x in YBaCo2Ox, which has largely distorted Co orbitals because of the small size of Y3+, has so far been limited to 5.52. To expand the available range of x, in this study, we performed a low-temperature topotactic oxidation of YBaCo2O5.3 epitaxial films using a strong oxidizing agent NaClO. The x value can be varied in a wide range of 5.3-6.0, maintaining the A-site cation-ordered perovskite structure, by changing the pH and temperature of NaClO. The single crystalline film with x = 6 exhibits large tetragonal distortion (c/a = 0.968) because of the small ionic radius of Y3+ and substrate-induced tensile strain. Unlike antiferromagnetic insulating YBaCo2O5.5, the fully oxidized film with x = 6 exhibits in-plane ferromagnetism and metallicity with a Curie temperature of 130 K possibly because of the double-exchange interaction between Co3+ and Co4+. Moreover, the YBaCo2O6 film exhibits huge magnetic anisotropy with a magnetic anisotropy constant of 1.5 x 10(8) erg cm(-3), demonstrating that the A-site cation-ordered perovskite structure is promising for obtaining high magnetocrystalline anisotropic materials.
• Ferrimagnetism and Ferroelectricity in Cr-Substituted GaFeO3 Epitaxial Films

  Tsukasa Katayama, Shintaro Yasui, Takuya Osakabe, Yosuke Hamasaki, Mitsuru Itoh

  Chemistry of Materials 30 4 1436 - 1441 2018年
• Epitaxial thin film growth of garnet-, GdFeO3-, and YMnO3-type LuFeO3 using pulsed laser deposition

  Tsukasa Katayama, Yosuke Hamasaki, Shintaro Yasui, Akiko Miyahara, Mitsuru Itoh

  Thin Solid Films 642 41 - 44 2017年11月
• κ-アルミナ型酸化物強誘電体の構造と強誘電性

  伊藤 満, 片山 司, 安井 伸太郎, 谷山 智康, 森分 博紀, 小西 綾子, 木口 賢紀, 白石 貴久, 赤間 章裕, 濱嵜 容丞

  日本物理学会講演概要集 72.2 2321 - 2321 一般社団法人 日本物理学会 2017年
• Electric Transport Characteristics of Gallium Iron Oxide Epitaxial Thin Film

  Katayama, Tsukasa, Yasui, Shintaro, Hamasaki, Yosuke, Itoh, Mitsuru

  Mrs Advances 2 56 2017年
• Topotactic fluorination of perovskite strontium ruthenate thin films using polyvinylidene fluoride

  Kawahara, K., Chikamatsu, A., Katayama, T., Onozuka, T., Ogawa, D., Morikawa, K., Ikenaga, E., Hirose, Y., Harayama, I., Sekiba, D., Fukumura, T., Hasegawa, T.

  Crystengcomm 19 2 313 - 317 2017年 

  We investigated the polyvinylidene fluoride (PVDF)-mediated topotactic fluorination of two perovskite ruthenate thin films with different crystallographic structures, non-layered perovskite SrRuO3 and layered perovskite Sr2RuO4. While the former ruthenate did not react with PVDF, the latter was fluorinated to form Sr2RuO3F2 with a structure that exhibited a largely expanded c-axis. These results indicate that fluorine ions are preferentially inserted into the SrO rocksalt blocks in perovskite ruthenates, and that the oxygen atoms in the precursor oxide were partially removed upon fluorination. Finally, we noted that the Sr2RuO3F2 film was insulating, with a resistivity of 4.1 × 10 Ω cm at 300 K. It should be noted that this resistivity is five orders of magnitude higher than that of the metallic Sr2RuO4 film (6.7 × 104 Ω cm).
• Reversible Changes in Resistance of Perovskite Nickelate NdNiO3 Thin Films Induced by Fluorine Substitution

  Onozuka, Tomoya, Chikamatsu, Akira, Katayama, Tsukasa, Hirose, Yasushi, Harayama, Isao, Sekiba, Daiichiro, Ikenaga, Eiji, Minohara, Makoto, Kumigashira, Hiroshi, Hasegawa, Tetsuya

  Acs Applied Materials & Interfaces 9 12 10882 - 10887 2017年 

  Perovskite nickel oxides are of fundamental as well as technological interest because they show large resistance modulation associated with phase transition as a function of the temperature and chemical composition. Here, the effects of fluorine doping in perovskite nickelate NdNiO3 epitaxial thin films are investigated through a low-temperature reaction with polyvinylidene fluoride as the fluorine source. The fluorine content in the fluorinated NdNiO3-xFx films is controlled with precision by varying the reaction time. The fully fluorinated film (x approximate to 1) is highly insulating and has a bandgap of 2.1 eV, in contrast to NdNiO3, which exhibits metallic transport properties. Hard X-ray photoelectron and soft X-ray absorption spectroscopies reveal the suppression of the density of states at the Fermi level as well as the reduction of nickel ions (valence state changes from +3 to +2) after fluorination, suggesting that the strong Coulombic repulsion in the Ni 3d orbitals associated with the fluorine substitution drives the metal-to-insulator transition. In addition, the resistivity of the fluorinated films recovers to the original value for NdNiO3 after annealing in an oxygen atmosphere. By application of the reversible fluorination process to transition-metal oxides, the search for resistance-switching materials could be accelerated.
• First-Principles Calculations on the Crystal/Electronic Structure and Phase Stability of H-Doped SrFeO2

  Kurauchi, Yuji, Kamisaka, Hideyuki, Katayama, Tsukasa, Chikamatsu, Akira, Hasegawa, Tetsuya

  Journal of Physical Chemistry C 121 13 2017年
• Control of crystal-domain orientation in multiferroic Ga0.6Fe1.4O3 epitaxial thin films

  Katayama, Tsukasa, Yasui, Shintaro, Hamasaki, Yosuke, Itoh, Mitsuru

  Applied Physics Letters 110 21 2017年
• Chemical tuning of room-temperature ferrimagnetism and ferroelectricity in ε-Fe2O3-type multiferroic oxide thin films

  Tsukasa Katayama, Shintaro Yasui, Yosuke Hamasaki, Takuya Osakabe, Mitsuru Itoh

  Journal of Materials Chemistry C 2017年
• Topotactic reductive synthesis of A-site cation-ordered perovskite YBaCo

  Katayama Tsukasa, Chikamatsu Akira, Fukumura Tomoteru, Hasegawa Tetsuya

  Jpn. J. Appl. Phys. 55 4 04EJ05  Institute of Physics 2016年 

  A-site cation-ordered perovskite YBaCo2Oxepitaxial films were synthesized by combining pulsed-laser deposition and topotactic reduction using CaH2. The oxygen contents (x) of the films could be controlled in a range of 4.5–5.5 by adjusting the reaction temperature. The c-axis length of the YBaCo2Oxfilms decreased with decreasing x when x ≥ 5.3 but drastically increased when x ∼ 4.5. In contrast, the in-plane lattice constants remained locked-in by the substrate after the reaction. The metal insulator transition observed in bulk YBaCo2O5.5was substantially suppressed in the present film, likely because of the epitaxial strain effect. The resistivity of the films was significantly enhanced by changing the x value from ∼5.5 to ∼4.5, reflecting the distortion of the CoOxlayers.
• Formation of defect-fluorite structured NdNiOxHy epitaxial thin films via a soft chemical route from NdNiO3 precursors

  Onozuka, T., Chikamatsu, A., Katayama, T., Fukumura, T., Hasegawa, T.

  Dalton Transactions 45 30 2016年
• Experimental and theoretical investigation of electronic structure of SrFeO

  Katayama Tsukasa, Chikamatsu Akira, Kamisaka Hideyuki, Kumigashira Hiroshi, Hasegawa Tetsuya

  Appl. Phys. Express 9 2 25801 - 25801 Institute of Physics 2016年 

  We investigated the electronic structure of perovskite SrFeO3−xFx(0.6 ≤ x ≤ 1) films by optical absorption, photoemission, and X-ray absorption spectroscopies, as well as density functional theory (DFT)-based calculations. The optical bandgap expanded with x, yielding a wider direct bandgap for the SrFeO2F film than for the LaFeO3film. The DFT calculations suggested that the majority of FeO4F2octahedra in the SrFeO2F film had cis configurations and that the enlarged bandgap mainly originated from bond bending in the O–Fe–O chains. We experimentally observed the valence and conduction bands of the SrFeO2F film, and found them to be qualitatively consistent with the results of DFT-based calculations.
• Epitaxial growth and electronic structure of oxyhydride SrVO2H thin films

  Katayama, Tsukasa, Chikamatsu, Akira, Yamada, Keisuke, Shigematsu, Kei, Onozuka, Tomoya, Minohara, Makoto, Kumigashira, Hiroshi, Ikenaga, Eiji, Hasegawa, Tetsuya

  Journal of Applied Physics 120 8 2016年
• Topotactic synthesis of strontium cobalt oxyhydride thin film with perovskite structure

  Katayama, Tsukasa, Chikamatsu, Akira, Kamisaka, Hideyuki, Yokoyama, Yuichi, Hirata, Yasuyuki, Wadati, Hiroki, Fukumura, Tomoteru, Hasegawa, Tetsuya

  AIP Advances 5 10 2015年
• Topotactic reductive fluorination of strontium cobalt oxide epitaxial thin films

  Katayama, Tsukasa, Chikamatsu, Akira, Hirose, Yasushi, Fukumura, Tomoteru, Hasegawa, Tetsuya

  Journal of Sol-Gel Science and Technology 73 3 2015年
• Effects of Cr substitution on the magnetic and transport properties and electronic states of SrRuO3 epitaxial thin films

  Kurita, Kaori, Chikamatsu, Akira, Shigematsu, Kei, Katayama, Tsukasa, Kumigashira, Hiroshi, Fukumura, Tomoteru, Hasegawa, Tetsuya

  Physical Review B 92 11 2015年
• Topotactic fluorination of strontium iron oxide thin films using polyvinylidene fluoride

  Katayama, T., Chikamatsu, A., Hirose, Y., Takagi, R., Kamisaka, H., Fukumura, T., Hasegawa, T.

  Journal of Materials Chemistry C 2 27 2014年
• Metallic conductivity in infinite-layer strontium iron oxide thin films reduced by calcium hydride

  Katayama, T., Chikamatsu, A., Hirose, Y., Kumigashira, H., Fukumura, T., Hasegawa, T.

  Journal of Physics D-Applied Physics 47 13 2014年
• Electronic and transport properties of Eu-substituted infinite-layer strontium ferrite thin films

  Chikamatsu, Akira, Matsuyama, Toshiya, Katayama, Tsukasa, Hirose, Yasushi, Kumigashira, Hiroshi, Oshima, Masaharu, Fukumura, Tomoteru, Hasegawa, Tetsuya

  Journal of Crystal Growth 378 2013年

その他活動・業績

• 水溶性Sr₃Al₂O₆薄膜を用いたフリースタンディングPSCTO単結晶薄膜の作製とその蛍光特性

  太宰卓朗, 安井伸太郎, 片山司, 谷山智康, 谷山智康, 伊藤満 応用物理学会春季学術講演会講演予稿集(CD-ROM) 66th 2019年
• マルチフェロイックh-DyFeO₃薄膜の誘電・磁気特性

  笠原淳, 片山司, MO S., 近松彰, 安井伸太郎, 伊藤満, 長谷川哲也 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年
• マルチフェロイックFe₂Mo₃O₈薄膜における磁気転移温度の向上

  MO S., 片山司, 近松彰, 芝田悟朗, 芝田悟朗, 藤森淳, 安井伸太郎, 伊藤満, 長谷川哲也 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年
• GaFeO₃単結晶基板を用いたSc_0.5Fe_1.5O₃薄膜の単ドメイン化

  立山昂輝, 片山司, 越阪部拓也, 太宰卓朗, YU Jianding, HE Huan, WANG Hui, 濱嵜容丞, 安井伸太郎, 谷山智康, 伊藤満 セラミックス基礎科学討論会講演要旨集 56th 2018年
• パルスレーザー堆積法によるFe₂Mo₃O₈エピタキシャル膜の合成

  毛司辰, 片山司, 近松彰, 安井伸太郎, 伊藤満, 長谷川哲也 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 79th 2018年
• κ-Al₂O₃型(A,Fe)₂O₃(A=Al,Ga,Fe,Sc,Rh,In)酸化物の強誘電性と磁性

  伊藤満, 濱嵜容丞, 片山司, 越阪部拓也, 安井伸太郎, 谷山智康 日本物理学会講演概要集(CD-ROM) 72 (1) 2017年
• κ-Al₂O₃型(A,Fe)₂O₃(A=Al,Ga,Fe,Rh,Sc,In)薄膜の磁性と強誘電性

  伊藤満, 濱嵜容丞, 片山司, 安井伸太郎, 谷山智康 日本化学会春季年会講演予稿集(CD-ROM) 97th 2017年
• 元素置換サイト設計による室温マルチフェロイックGaFeO₃型酸化物薄膜の磁気誘電特性制御

  片山司, 安井伸太郎, 浜嵜容丞, 越阪部拓也, 伊藤満 応用物理学会春季学術講演会講演予稿集(CD-ROM) 64th 2017年
• マルチフェロイックGaFeO₃薄膜の磁気及び強誘電特性へのCr置換効果

  越阪部拓也, 片山司, 安井伸太郎, 谷山智康, 伊藤満 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 78th 2017年
• GaFeO₃型マルチフェロイック材料のドメイン構造

  片山司, 安井伸太郎, 浜嵜容丞, 森分博紀, 小西綾子, 木口賢紀, 白石貴久, 赤間章裕, 伊藤満 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 78th 2017年
• ε-Fe₂O₃薄膜の構造と磁気特性へのRh置換効果

  越阪部拓也, 浜嵜容丞, 片山司, 安井伸太郎, 谷山智康, 伊藤満 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 77th 2016年
• マルチフェロイックGa_xFe_2-xO₃薄膜の磁気誘電特性

  片山司, 浜嵜容丞, 安井伸太郎, 伊藤満 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 77th 2016年

教育活動情報

主要な担当授業