Organization
Institute of Integrated Research Materials and Structures Laboratory Visiting Professor
Title
Visiting Professor
External link
YAMAMOTO TAKAFUMI
News & Topics
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New Insight for Stabilizing Halide Perovskite via Thiocyanate Substitution
2023/08/31
Languages： English
α-FAPbI3, a promising solar cell material with a cubic perovskite structure that is metastable at room temperature, can be stabilized by introducing a pseudo-halide ion like thiocyanate (SCN–) in
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一次元の欠陥が整列した新しい有機−無機ハイブリッド化合物 ペロブスカイト太陽電池の耐久性向上に期待
2023/08/31
Languages： Japanese
要点-チオシアン酸イオンを導入した新しい有機−無機ハイブリッド化合物の合成と結晶構造の解明に成功。-得られた化合物がペロブスカイト構造の安定化に寄与することを発見。-ペロブスカイト太陽電池の耐久性向上に期待。概要東京工業大学物質理工学院材料
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超高圧合成、添加剤が選択的物質合成の決め手に 電池材料等への応用に期待
2023/07/26
Languages： Japanese
要点-超高圧合成において、添加剤を加えることで新規酸水素化物の合成に成功。-得られた物質はリチウムイオン電池の負極材料として高い性能を示す。-新機能材料の新たな合成技術として期待される。概要東京工業大学物質理工学院材料系の鈴木仁哉大学院生（
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A High-Pressure Flux Method to Synthesize High-Purity Oxyhydrides
2023/07/25
Languages： English
Adding a flux during the synthesis of oxyhydrides is a promising strategy to obtain a pure, homogenous product, reveal scientists from Tokyo Tech. An SrCl2 flux promoted the melting of a part of
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Advanced X-Ray Technique Unveils Fast Solid-Gas Chemical Reaction Pathways
2023/05/02
Languages： English
Short-lived intermediate phases in solid-gas reactions can be captured with high-speed time-resolved synchrotron X-ray diffraction technique, demonstrate Tokyo Tech researchers. Their observation
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2023/05/02
Languages： Japanese
要点-自動車の排ガス浄化に有効な酸素貯蔵材料における、高速酸素脱離反応を可視化。-瞬きの速度で移り変わる高速反応を時分割X線回折測定で連続撮影することに成功。-機能性材料の設計指針の構築や反応最適化につながる技術として期待。概要東京工業大学科
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2020/11/24
Languages： Japanese
要点-酸化物合成において応力を与えることで原子空孔面の方向や周期の制御に成功-エネルギーランドスケープに立脚した酸化物の合理的設計への道を拓く-今後、電気・光変換機能や高い転移温度をもつ超伝導など、革新的機能材料の開発が期待される概要東京工業大学科学技術創成研究院フロンティア材料研究所山本隆文准教授
Research Areas
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Nanotechnology/Materials / Inorganic compounds and inorganic materials chemistry
Papers
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Designing Iron-Based Layered Perovskite Oxides with Optimized Oxygen Storage Performance and Structural Stability
Taiki Kosuge, Chika Yamazoe, Shogo Kawaguchi, Shintaro Kobayashi, Naoto Nagata, Masaki Azuma, Saburo Hosokawa, Takafumi Yamamoto
Chemistry of Materials 2025.10
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Dimensional Reduction of Perovskite-Derived Structures in Formamidinium-Rich Lead Iodide Compositions
Takuya Ohmi, Wataru Taniguchi, Bhawna Bhawna, Tomoya Fukui, Yuki Haruta, Takayuki Nakanishi, Takanori Fukushima, Makhsud. I. Saidaminov, Masaki Azuma, Takafumi Yamamoto
2025.10
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Geometric Isomers of Bipyridinium in Lead Halide Perovskitoids
Takuya Ohmi, Soumya Kundu, Hanyang Ye, Wen Zhou, Kanta Ogawa, Yuki Haruta, Alejandra M. Navarrete-López, Takafumi Yamamoto, Makhsud I. Saidaminov
Inorganic Chemistry 2025.6
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Colossal Thermal Expansion in Ca-Substituted PbCrO3
Qiumin Liu, Takumi Nishikubo, Kazuki Takahashi, Seiho Higashi, Yusuke Shibata, Jun Miyake, Kano Hatayama, Yuki Sakai, Teppei Nagase, Koki Matsushima, Runze Yu, Takafumi Yamamoto, Masaki Azuma
Chemistry of Materials 2025.3
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Crystal structure and magnetoresistance of vacancy-ordered perovskite SrV0.3Fe0.7O2.8 at low temperature
Teppei Nagase, Takumi Nishikubo, Yuki Sakai, Kei Shigematsu, Ko Mibu, Masato Hagihala, Masaki Azuma, Takafumi Yamamoto
CrystEngComm 2025
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Tunable optical properties in the (110)p-oriented layered halide perovskite FA4Pb2I7.5(SCN)0.5 by Br substitution
Koki Matsushima, Takuya Ohmi, Wataru Taniguchi, Shoya Nagano, Tomoya Fukui, Takanori Fukushima, Muhammad Awais, Makhsud Saidaminov, Masaki Azuma, Takafumi Yamamoto
Dalton Transactions 2025
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Rapid In Situ Investigation of Nitride Synthesis: Ambient Atmospheric Nitridation of 3d Metal Oxides Using Dicyandiamide
Momoka Demura, Keigo Ono, Masanori Nagao, Takafumi Yamamoto, Chul-Ho Lee, Aichi Yamashita, Chikako Moriyoshi, Shohei Tada, Yuji Masubuchi, Yuta Fujii, Kiyoharu Tadanaga, Akira Miura
Chemistry of Materials 2024.12
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FA4Pb2I7.5(SCN)0.5: n = 3 Member of Perovskite Homologous Series FAn+1Pbn−1I3n−1.5(SCN)0.5 with Columnar Defects
Takuya Ohmi, James R. Neilson, Wataru Taniguchi, Tomoya Fukui, Teppei Nagase, Yuki Haruta, Makhsud I. Saidaminov, Takanori Fukushima, Masaki Azuma, Takafumi Yamamoto
ACS Materials Letters 2024.5
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Synthesis and Structure of Vacancy-Ordered Perovskite Ba6Ta2Na2X2O17 (X = P, V): Significance of Structural Model Selection on Discovered Compounds
Takafumi Yamamoto, Yuya Otsubo, Teppei Nagase, Taiki Kosuge, Masaki Azuma
Inorganic Chemistry 2024.3
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Synthesis and Structure of Vacancy-Ordered Perovskite Ba6Ta2Na2X2O17 (X = P, V): Significance of Structural Model Selection on Discovered Compounds
Takafumi Yamamoto, Yuya Otsubo, Teppei Nagase, Taiki Kosuge, Masaki Azuma
2023.12
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3D Visualization of Morphological Evolution of Large Defects during Spark Plasma Sintering of Alumina Granules
Gaku Okuma, Masaya Endo, Haruki Minagawa, Ryo Inoue, Hideki Kakisawa, Takuma Kohata, Toshio Osada, Takafumi Yamamoto, Masaki Azuma, Akihisa Takeuchi, Masayuki Uesugi, Olivier Guillon, Fumihiro Wakai
Advanced Engineering Materials 2023.9
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Thiocyanate-Stabilized Pseudo-cubic Perovskite CH(NH2)2PbI3 from Coincident Columnar Defect Lattices
Takuya Ohmi, Iain W. H. Oswald, James R. Neilson, Nikolaj Roth, Shunta Nishioka, Kazuhiko Maeda, Kotaro Fujii, Masatomo Yashima, Masaki Azuma, Takafumi Yamamoto
Journal of the American Chemical Society 145 ( 36 ) 19759 - 19767 2023.8
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Selective Synthesis of Perovskite Oxyhydrides Using a High-Pressure Flux Method
Jinya Suzuki, Hiroyasu Okochi, Naoki Matsui, Teppei Nagase, Haruki Tochizawa, Hiroki Sahara, Takumi Nishikubo, Yuki Sakai, Takuya Ohmi, Zhao Pan, Takashi Saito, Hiroyuki Saitoh, Atsunori Ikezawa, Hajime Arai, Ryoji Kanno, Takafumi Yamamoto, Masaki Azuma
Journal of the American Chemical Society 145 ( 30 ) 16398 - 16405 2023.8
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Masahito Ikeda, Randy Jalem, Gen Hasegawa, Naoaki Kuwata, Qiumin Liu, Takafumi Yamamoto, Kei Shigematsu, Yoshitaka Tateyama, Masaki Azuma
The Journal of Physical Chemistry C 2023.7
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Takafumi Yamamoto, Shogo Kawaguchi, Taiki Kosuge, Akira Sugai, Naoki Tsunoda, Yu Kumagai, Kosuke Beppu, Takuya Ohmi, Teppei Nagase, Kotaro Higashi, Kazuo Kato, Kiyofumi Nitta, Tomoya Uruga, Seiji Yamazoe, Fumiyasu Oba, Tsunehiro Tanaka, Masaki Azuma, Saburo Hosokawa
Advanced Science 2023.4
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Zhenya Zhang, Fumiya Sekiguchi, Takahiro Moriyama, Shunsuke C. Furuya, Masahiro Sato, Takuya Satoh, Yu Mukai, Koichiro Tanaka, Takafumi Yamamoto, Hiroshi Kageyama, Yoshihiko Kanemitsu, Hideki Hirori
Nature Communications 14 ( 1 ) 2023.3
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Selective CO2 Fixation to Styrene Oxide by Ta-Substitution of Lindqvist-Type [(Ta,Nb)(6)O-19](8-) Clusters
Vorakit Chudatemiya, Mio Tsukada, Hiroki Nagakari, Soichi Kikkawa, Jun Hirayama, Naoki Nakatani, Takafumi Yamamoto, Seiji Yamazoe
CATALYSTS 13 ( 2 ) 2023.2
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Ultralow thermal conductivity in the mixed-anion solid solution Sn2SbS2−xSexI3
Justin Mark, Wenhao Zhang, Kazuhiko Maeda, Takafumi Yamamoto, Hiroshi Kageyama, Takao Mori
Journal of Materials Chemistry A 2023
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Takafumi Yamamoto
Advanced Engineering Materials 2023
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High-pressure behavior of tetragonal barium carbodiimide, BaNCN
Yuji Masubuchi, Suzuka Miyazaki, Peng Song, Takafumi Yamamoto, Kosuke Nakano, Kenta Hongo, Ryo Maezono
JOURNAL OF ALLOYS AND COMPOUNDS 918 2022.10
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Temperature-induced structural transition in an organic-inorganic hybrid layered perovskite (MA)(2)PbI2-xBrx(SCN)(2)
Takuya Ohmi, Tomoaki Miura, Kei Shigematsu, Alexandra A. Koegel, Brian S. Newell, James R. Neilson, Tadaaki Ikoma, Masaki Azuma, Takafumi Yamamoto
CRYSTENGCOMM 24 ( 30 ) 5428 - 5434 2022.8
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Bulk charge density wave and electron-phonon coupling in superconducting copper oxychlorides
L. Chaix, B. Lebert, H. Miao, A. Nicolaou, F. Yakhou, H. Cercellier, S. Grenier, N. B. Brookes, A. Sulpice, S. Tsutsui, A. Bosak, L. Paolasini, D. Santos-Cottin, H. Yamamoto, I. Yamada, M. Azuma, T. Nishikubo, T. Yamamoto, M. Katsumata, M. P. M. Dean, M. d'Astuto
Physical Review Research 4 ( 3 ) 2022.7
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Polyoxocationic antimony oxide cluster with acidic protons
Yuki Watanabe, Kim Hyeon-Deuk, Takafumi Yamamoto, Masayoshi Yabuuchi, Olesia M. Karakulina, Yasuto Noda, Takuya Kurihara, I-Ya Chang, Masanobu Higashi, Osamu Tomita, Cédric Tassel, Daichi Kato, Jingxin Xia, Tatsuhiko Goto, Craig M. Brown, Yuto Shimoyama, Naoki Ogiwara, Joke Hadermann, Artem M. Abakumov, Sayaka Uchida, Ryu Abe, Hiroshi Kageyama
Science Advances 8 ( 24 ) 2022.6
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SrV0.3Fe0.7O2.8: A Vacancy-Ordered Fe-Based Perovskite Exhibiting Room-Temperature Magnetoresistance
Teppei Nagase, Takumi Nishikubo, Masayuki Fukuda, Yuki Sakai, Kei Shigematsu, Yoichi Ikeda, Yusuke Nambu, Qiang Zhang, Masaaki Matsuda, Ko Mibu, Masaki Azuma, Takafumi Yamamoto
Inorganic Chemistry 61 ( 24 ) 8987 - 8991 2022.6
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Sequential Pressure-Induced B1–B2 Transitions in the Anion-Ordered Oxyhydride Ba2YHO3 Reviewed
Harry W. T. Morgan, Takafumi Yamamoto, Takumi Nishikubo, Takuya Ohmi, Takehiro Koike, Yuki Sakai, Masaki Azuma, Hirofumi Ishii, Genki Kobayashi, John E. McGrady
Inorganic Chemistry 2022.5
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PbBi<inf>3</inf>O<inf>4</inf>X<inf>3</inf> (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability
Hajime Suzuki, Masanobu Higashi, Osamu Tomita, Yusuke Ishii, Takafumi Yamamoto, Daichi Kato, Tetsu Kotani, Daichi Ozaki, Shunsuke Nozawa, Kouichi Nakashima, Koji Fujita, Akinori Saeki, Hiroshi Kageyama, Ryu Abe
Chemistry of Materials 33 ( 24 ) 9580 - 9587 2021.12
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Shogo Wakazaki, Qiumin Liu, Randy Jalem, Takumi Nishikubo, Yuki Sakai, Naoki Matsui, Guowei Zhao, Kota Suzuki, Kei Shigematsu, Takafumi Yamamoto, Ryoji Kanno, Hena Das, Yoshitaka Tateyama, Masaki Azuma
Chemistry of Materials 2021.11
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High-Pressure and High-Temperature Synthesis of Anion-Disordered Vanadium Perovskite Oxyhydrides
Kazumasa Miyazaki, Masayuki Ochi, Takumi Nishikubo, Jinya Suzuki, Takashi Saito, Takashi Kamiyama, Kazuhiko Kuroki, Takafumi Yamamoto, Masaki Azuma
Inorganic Chemistry 60 ( 20 ) 15751 - 15758 2021.10
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Enhanced Magnetic Interaction by Face-Shared Hydride Anions in 6H-BaCrO2H
Kentaro Higashi, Masayuki Ochi, Yusuke Nambu, Takafumi Yamamoto, Taito Murakami, Naoya Yamashina, Cédric Tassel, Yuki Matsumoto, Hiroshi Takatsu, Craig M. Brown, Hiroshi Kageyama
Inorganic Chemistry 60 ( 16 ) 11957 - 11963 2021.8
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Base Catalysis of Sodium Salts of [Ta6−xNbxO19]8− Mixed-Oxide Clusters
Soichi Kikkawa, Mio Tsukada, Kanako Shibata, Yu Fujiki, Kazuki Shibusawa, Jun Hirayama, Naoki Nakatani, Takafumi Yamamoto, Seiji Yamazoe
Symmetry 13 ( 7 ) 1267 - 1267 2021.7
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Pressure-Induced Collapse Transition in BaTi2Pn2O (Pn = As, Sb) with an Unusual Pn–Pn Bond Elongation International journal
Takafumi Yamamoto, Takeshi Yajima, Zhi Li, Takateru Kawakami, Kousuke Nakano, Takami Tohyama, Takehiko Yagi, Yoji Kobayashi, Hiroshi Kageyama
Inorganic Chemistry 2021.2
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Conduction Band Control of Oxyhalides with a Triple-Fluorite Layer for Visible Light Photocatalysis
Nakada, Akinobu, Kato, Daichi, Nelson, Ryky, Takahira, Hikaru, Yabuuchi, Masayoshi, Higashi, Masanobu, Suzuki, Hajime, Kirsanova, Maria, Kakudou, Naoji, Tassel, Cédric, Yamamoto, Takafumi, Brown, Craig M., Dronskowski, Richard, Saeki, Akinori, Abakumov, Artem, Kageyama, Hiroshi, Abe, Ryu
Journal of the American Chemical Society 143 ( 6 ) 2491 - 2499 2021
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Structure and Optical Properties of Layered Perovskite (MA)2PbI2–xBrx(SCN)2 (0 ≤ x < 1.6)
Takafumi Yamamoto, Iain W. H. Oswald, Christopher N. Savory, Takuya Ohmi, Alexandra A. Koegel, David O. Scanlon, Hiroshi Kageyama, James R. Neilson
Inorganic Chemistry 59 ( 23 ) 17379 - 17384 2020.12
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Strain-induced creation and switching of anion vacancy layers in perovskite oxynitrides
Takafumi Yamamoto, Akira Chikamatsu, Shunsaku Kitagawa, Nana Izumo, Shunsuke Yamashita, Hiroshi Takatsu, Masayuki Ochi, Takahiro Maruyama, Morito Namba, Wenhao Sun, Takahide Nakashima, Fumitaka Takeiri, Kotaro Fujii, Masatomo Yashima, Yuki Sugisawa, Masahito Sano, Yasushi Hirose, Daiichiro Sekiba, Craig M. Brown, Takashi Honda, Kazutaka Ikeda, Toshiya Otomo, Kazuhiko Kuroki, Kenji Ishida, Takao Mori, Koji Kimoto, Tetsuya Hasegawa, Hiroshi Kageyama
Nature Communications 11 ( 1 ) 2020.12
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Responsive four‐coordinate Fe(II) nodes in FePd(CN)4 Reviewed
Ryo Ohtani, Hiromu Matsunari, Takafumi Yamamoto, Koji Kimoto, Masaaki Isobe, Kotaro Fujii, Masatomo Yashima, Susumu Fujii, Akihide Kuwabara, Yuh Hijikata, Shin-ichiro Noro, Masaaki Ohba, Hiroshi Kageyama, Shinya Hayami
Angewandte Chemie International Edition 59 ( 43 ) 19254 - 19259 2020.7
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Observation of Stabilized Monoclinic Phase as a “Bridge” at the Morphotropic Phase Boundary between Tetragonal Perovskite PbVO3 and Rhombohedral BiFeO3
Zhao Pan, Takumi Nishikubo, Yuki Sakai, Takafumi Yamamoto, Shogo Kawaguchi, Masaki Azuma
Chemistry of Materials 32 ( 8 ) 3615 - 3620 2020.4
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Robust Giant Tetragonal Distortion Coupled with High-Spin Co3+ in Electron-Doped BiCoO3
Hayato Ishizaki, Hajime Yamamoto, Takumi Nishikubo, Yuki Sakai, Shogo Kawaguchi, Keisuke Yokoyama, Yoichi Okimoto, Shin-ya Koshihara, Takafumi Yamamoto, Masaki Azuma
Inorganic Chemistry 58 ( 23 ) 16059 - 16064 2019.12
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Pressure-Induced Transitions in the 1-Dimensional Vanadium Oxyhydrides Sr2VO3H and Sr3V2O5H2, and Comparison to 2-Dimensional SrVO2H
Takafumi Yamamoto, Harry W. T. Morgan, Dihao Zeng, Takateru Kawakami, Midori Amano Patino, Michael A. Hayward, Hiroshi Kageyama, John E. McGrady
Inorganic Chemistry 58 ( 22 ) 15393 - 15400 2019.11
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Realization of interlayer ferromagnetic interaction in MnSb2Te4 toward the magnetic Weyl semimetal state Reviewed
Taito Murakami, Yusuke Nambu, Takashi Koretsune, Gu Xiangyu, Takafumi Yamamoto, Craig M. Brown, Hiroshi Kageyama
PHYSICAL REVIEW B 100 ( 19 ) 2019.11
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Exploring Structures and Properties through Anion Chemistry Reviewed
Kageyama Hiroshi, Yajima Takeshi, Tsujimoto Yoshihiro, Yamamoto Takafumi, Tassel Cedric, Kobayashi Yoji
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 92 ( 8 ) 1349 - 1357 2019.8
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Band Engineering of Double-Layered Sillén–Aurivillius Perovskite Oxychlorides for Visible-Light-Driven Water Splitting Reviewed
Akinobu Nakada, Masanobu Higashi, Takuma Kimura, Hajime Suzuki, Daichi Kato, Hiroyuki Okajima, Takafumi Yamamoto, Akinori Saeki, Hiroshi Kageyama, Ryu Abe
Chemistry of Materials 31 ( 9 ) 3419 - 3429 2019.5
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Highly Correlated Hydride Ion Tracer Diffusion in SrTiO3–xHx Oxyhydrides Reviewed
Xin Liu, Tor Svendsen Bjørheim, Lasse Vines, Øystein Slagtern Fjellvåg, Cecilie Granerød, Øystein Prytz, Takafumi Yamamoto, Hiroshi Kageyama, Truls Norby, Reidar Haugsrud
Journal of the American Chemical Society 141 ( 11 ) 4653 - 4659 2019.3
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High-Pressure Synthesis of A(2)NiO(2)Ag(2)Se(2) (A=Sr, Ba) with a High-Spin Ni2+ in Square-Planar Coordination Reviewed
Matsumoto Yuki, Yamamoto Takafumi, Nakano Kousuke, Takatsu Hiroshi, Murakami Taito, Hongo Kenta, Maezono Ryo, Ogino Hiraku, Song Dongjoon, Brown Craig M, Tassel Cedric, Kageyama Hiroshi
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 58 ( 3 ) 756 - 759 2019.1
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Metal-Dependent Support Effects of Oxyhydride-Supported Ru, Fe, Co Catalysts for Ammonia Synthesis Reviewed
Tang Ya, Kobayashi Yoji, Masuda Naoya, Uchida Yoshinori, Okamoto Hiroki, Kageyama Toki, Hosokawa Saburo, Loyer Francois, Mitsuhara Kei, Yamanaka Keisuke, Tamenori Yusuke, Tassel Cedric, Yamamoto Takafumi, Tanaka Tsunehiro, Kageyama Hiroshi
ADVANCED ENERGY MATERIALS 8 ( 36 ) 2018.12
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Taito Murakami, Takafumi Yamamoto, Amit Kumar, Seikh M. Yusuf, Hiroshi Kageyama
Journal of Solid State Chemistry 263 190 - 194 2018.7
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AgFeOF2: A Fluorine-Rich Perovskite Oxyfluoride Reviewed
Fumitaka Takeiri, Takafumi Yamamoto, Naoaki Hayashi, Saburo Hosokawa, Kazunari Arai, Jun Kikkawa, Kazutaka Ikeda, Takashi Honda, Toshiya Otomo, Cedric Tassel, Koji Kimoto, Hiroshi Kageyama
INORGANIC CHEMISTRY 57 ( 11 ) 6686 - 6691 2018.6
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Promoted hydride/oxide exchange reaction in SrTiO3 by introduction of anion vacancy Reviewed
Takeiri Fumitaka, Yamamoto Takafumi, Kobayashi Yoji, Kageyama Hiroshi
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 255 2018.3
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Selective Hydride Occupation in BaVO3-xHx (0.3 ≤ × ≤ 0.8) with Faceand Corner-Shared Octahedra Reviewed
Takafumi Yamamoto, Kazuki Shitara, Shunsaku Kitagawa, Akihide Kuwabara, Masahiro Kuroe, Kenji Ishida, Masayuki Ochi, Kazuhiko Kuroki, Kotaro Fujii, Masatomo Yashima, Craig M. Brown, Hiroshi Takatsu, Cedric Tassel, Hiroshi Kageyama
Chemistry of Materials 30 ( 5 ) 1566 - 1574 2018.3
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Hydride-Enhanced CO2 Methanation: Water-Stable BaTiO2.4H0.6 as a New Support Reviewed
Tang Ya, Kobayashi Yoji, Tassel Cedric, Yamamoto Takafumi, Kageyama Hiroshi
Advanced Energy Materials 8 ( 23 ) 2018
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Heavy interstitial hydrogen doping into SrTiO3 Reviewed
Ryo Nakayama, Mitsuhiko Maesato, Takafumi Yamamoto, Hiroshi Kageyama, Takahito Terashima, Hiroshi Kitagawa
Chemical Communications 2018
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High pressure synthesis of hydride-fluoride pyrochlore NaCaMg2F7 1 xHx Reviewed
Kazunari Arai, Yoji Kobayashi, Ya Tang, Yusuke Tsutsui, Daisuke Sakamaki, Takafumi Yamamoto, Kotaro Fujii, Masatomo Yashima, Shu Seki, Hiroshi Kageyama
Chemistry Letters 47 ( 7 ) 829 - 832 2018
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Suppression of H-/O2- exchange by incorporated nitride anions in the perovskite lattice Reviewed
Fumitaka Takeiri, Takeshi Yajima, Takafumi Yamamoto, Yoji Kobayashi, Toshiaki Matsui, James Hester, Hiroshi Kageyama
JOURNAL OF SOLID STATE CHEMISTRY 256 33 - 37 2017.12
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Effect of Fe-site Substitution on Pressure-induced Spin Transition in SrFeO2 Reviewed
Takateru Kawakami, Takafumi Yamamoto, Kanami Yata, Minoru Ishii, Yoshitaka Watanabe, Masaichiro Mizumaki, Naomi Kawamura, Naoki Ishimatsu, Hiroki Takahashi, Taku Okada, Takehiko Yagi, Hiroshi Kageyama
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 86 ( 12 ) 2017.12
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Fumitaka Takeiri, Kohei Aidzu, Takeshi Yajima, Toshiaki Matsui, Takafumi Yamamoto, Yoji Kobayashi, James Hester, Hiroshi Kageyama
INORGANIC CHEMISTRY 56 ( 21 ) 13035 - 13040 2017.11
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Takafumi Yamamoto, Dihao Zeng, Takateru Kawakami, Vaida Arcisauskaite, Kanami Yata, Midori Amano Patino, Nana Izumo, John E. McGrady, Hiroshi Kageyama, Michael A. Hayward
NATURE COMMUNICATIONS 8 ( 1 ) 2017.10
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On Hydride Diffusion in Transition Metal Perovskite Oxyhydrides Investigated via Deuterium Exchange Reviewed
Ya Tang, Yoji Kobayashi, Kazuki Shitara, Ayako Konishi, Akihide Kuwabara, Takahide Nakashima, Cedric Tassel, Takafumi Yamamoto, Hiroshi Kageyama
CHEMISTRY OF MATERIALS 29 ( 19 ) 8187 - 8194 2017.10
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Valence Band Engineering by a Layer Insertion to Sillen-Aurivillius Perovskite Oxyhalides Reviewed
Daichi Kato, Cecile Herve, Takafumi Yamamoto, Hironobu Kunioku, Masanobu Higashi, Ryu Abe, Hiroshi Kageyama
CHEMISTRY LETTERS 46 ( 8 ) 1083 - 1085 2017.8
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Taito Murakami, Takafumi Yamamoto, Fumitaka Takeiri, Kousuke Nakano, Hiroshi Kageyama
INORGANIC CHEMISTRY 56 ( 9 ) 5041 - 5045 2017.5
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Cubic lead perovskite PbMoO3 with anomalous metallic behavior Reviewed
Hiroshi Takatsu, Olivier Hernandez, Wataru Yoshimune, Carmelo Prestipino, Takafumi Yamamoto, Cedric Tassel, Yoji Kobayashi, Dmitry Batuk, Yuki Shibata, Artem M. Abakumov, Craig M. Brown, Hiroshi Kageyama
Physical Review B 95 ( 15 ) 2017.4
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Selective and low temperature transition metal intercalation in layered tellurides Reviewed
Takeshi Yajima, Masaki Koshiko, Yaoqing Zhang, Tamio Oguchi, Wen Yu, Daichi Kato, Yoji Kobayashi, Yuki Orikasa, Takafumi Yamamoto, Yoshiharu Uchimoto, Mark A. Green, Hiroshi Kageyama
NATURE COMMUNICATIONS 7 2016.12
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ZnTaO2N: Stabilized High-Temperature LiNbO3-type Structure Reviewed
Yoshinori Kuno, Cedric Tassel, Koji Fujita, Dmitry Batuk, Artem M. Abakamov, Kazuki Shitara, Akihide Kuwabara, Hiroki Moriwake, Daichi Watabe, Clemens Ritter, Craig M. Brown, Takafumi Yamamoto, Fumitaka Takeiri, Ryu Abe, Yoji Kobayashi, Katsuhisa Tanaka, Hiroshi Kageyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 138 ( 49 ) 15950 - 15955 2016.12
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High-pressure synthesis of the layered iron oxyselenide BaFe2Se2O with strong magnetic anisotropy Reviewed
Fumitaka Takeiri, Yuki Matsumoto, Takafumi Yamamoto, Naoaki Hayashi, Zhi Li, Takami Tohyama, Cedric Tassel, Clemens Ritter, Yasuo Narumi, Masayuki Hagiwara, Hiroshi Kageyama
PHYSICAL REVIEW B 94 ( 18 ) 2016.11
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Takafumi Yamamoto, Hiroshi Ohkubo, Cedric Tassel, Naoaki Hayashi, Shota Kawasaki, Taku Okada, Takehiko Yagi, James Hester, Maxim Avdeev, Yoji Kobayashi, Hiroshi Kageyama
INORGANIC CHEMISTRY 55 ( 22 ) 12093 - 12099 2016.11
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High-Pressure Synthesis of Manganese Oxyhydride with Partial Anion Order Reviewed
Cedric Tassel, Yoshinori Goto, Daichi Watabe, Ya Tang, Honcheng Lu, Yoshinori Kuno, Fumitaka Takeiri, Takafumi Yamamoto, Craig M. Brown, James Hester, Yoji Kobayashi, Hiroshi Kageyama
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 55 ( 33 ) 9667 - 9670 2016.8
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HfMnSb2: A Metal-Ordered NiAs-type Pnictide with a Conical Spin Order Reviewed
Taito Murakami, Takafumi Yamamoto, Cedric Tassel, Hiroshi Takatsu, Clemens Ritter, Yoshitami Ajiro, Hiroshi Kageyama
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 55 ( 34 ) 9877 - 9880 2016.8
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Topochemical Nitridation with Anion Vacancy -Assisted N3-/O2- Exchange Reviewed
Riho Mikita, Tomoko Aharen, Takafumi Yamamoto, Fumitaka Takeiri, Tang Ya, Wataru Yoshimune, Koji Fujita, Suguru Yoshida, Katsuhisa Tanaka, Dmitry Batuk, Artem M. Abakumov, Craig M. Brown, Yoji Kobayashi, Hiroshi Kageyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 138 ( 9 ) 3211 - 3217 2016.3
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Y. Mukai, H. Hirori, T. Yamamoto, H. Kageyama, K. Tanaka
NEW JOURNAL OF PHYSICS 18 2016.1
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Pressure-Induced Transitions in Square Planar Coordinate Metal Oxides
YAMAMOTO Takafumi, KAGEYAMA Hiroshi
Nihon Kessho Gakkaishi 58 ( 6 ) 261 - 266 2016
-
Low temperature properties of the new lead perovskite PbMoO3
Takatsu Hiroshi, Yoshimune Wataru, Yamamoto Takafumi, Tassel Cedric, Kobayashi Yoji, Hernandez Olivier, Batuk Dmitry, Abakumov Artem M., Brown Craig, Kageyama Hiroshi
Meeting Abstracts of the Physical Society of Japan 71 1805 - 1805 2016
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High Pressure Electrical Resistance Mesurments of Sr(Fe0.8Co0.2)O2 and Sr(Fe0.8Mn0.2)O2
Yata Kanami, Kawakami Takateru, Murakawa Yosika, Yamamoto Takahumi, Kageyama Hirosi
Meeting Abstracts of the Physical Society of Japan 71 770 - 770 2016
-
A labile hydride strategy for the synthesis of heavily nitridized BaTiO3 Reviewed
Takeshi Yajima, Fumitaka Takeiri, Kohei Aidzu, Hirofumi Akamatsu, Koji Fujita, Wataru Yoshimune, Masatoshi Ohkura, Shiming Lei, Venkatraman Gopalan, Katsuhisa Tanaka, Craig M. Brown, Mark A. Green, Takafumi Yamamoto, Yoji Kobayashi, Hiroshi Kageyama
NATURE CHEMISTRY 7 ( 12 ) 1017 - 1023 2015.12
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Hydride in BaTiO2.5H0.5: A Labile Ligand in Solid State Chemistry Reviewed
Naoya Masuda, Yoji Kobayashi, Olivier Hernandez, Thierry Bataille, Serge Paofai, Hajime Suzuki, Clemens Ritter, Naoki Ichijo, Yasuto Noda, Kiyonori Takegoshi, Cedric Tassel, Takafumi Yamamoto, Hiroshi Kageyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137 ( 48 ) 15315 - 15321 2015.12
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Interlayer Communication in Aurivillius Vanadate to Enable Defect Structures and Charge Ordering Reviewed
Yaoqing Zhang, Takafumi Yamamoto, Mark A. Green, Hiroshi Kageyama, Yutaka Ueda
INORGANIC CHEMISTRY 54 ( 22 ) 10925 - 10933 2015.11
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Electrical Properties of Epitaxial Thin Films of Oxyhydrides ATiO(3-x)H(x) (A = Ba and Sr) Reviewed
Guillaume Bouilly, Takeshi Yajima, Takahito Terashima, Wataru Yoshimune, Kousuke Nakano, Cedric Tassel, Yoshiro Kususe, Koji Fujita, Katsuhisa Tanaka, Takafumi Yamamoto, Yoji Kobayashi, Hiroshi Kageyama
CHEMISTRY OF MATERIALS 27 ( 18 ) 6354 - 6359 2015.9
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Hongcheng Lu, Takafumi Yamamoto, Wataru Yoshimune, Naoaki Hayashi, Yoji Kobayashi, Yoshitami Ajiro, Hiroshi Kageyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137 ( 31 ) 9804 - 9807 2015.8
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Labile hydrogen: the reactivity of oxyhydrides Reviewed
Masuda Naoya, Hernandez Olivier, Tang Ya, Hosokawa Saburo, Tassel Cedric, Yamamoto Takafumi, Kobayashi Yoji, Kageyama Hiroshi
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 249 2015.3
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An Antiferro-to-Ferromagnetic Transition in EuTiO3-xHx Induced by Hydride Substitution Reviewed
Takafumi Yamamoto, Ryuta Yoshii, Guillaume Bouilly, Yoji Kobayashi, Koji Fujita, Yoshiro Kususe, Yoshitaka Matsushita, Katsuhisa Tanaka, Hiroshi Kageyama
INORGANIC CHEMISTRY 54 ( 4 ) 1501 - 1507 2015.2
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MnTaO2N: Polar LiNbO3-type Oxynitride with a Helical Spin Order Reviewed
Cedric Tassel, Yoshinori Kuno, Yoshihiro Goto, Takafumi Yamamoto, Craig M. Brown, James Hester, Koji Fujita, Masanobu Higashi, Ryu Abe, Katsuhisa Tanaka, Yoji Kobayashi, Hiroshi Kageyama
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 54 ( 2 ) 516 - 521 2015.1
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Terahertz Nonlinear Magnetic Response in Antiferromagnets Reviewed
Mukai Y, Hirori H, Yamamoto T, Kageyama H, Tanaka K, IEEE
2015 Conference on Lasers and Electro-Optics (Cleo) 2015
-
18pCD-2 Pressure-Induced Phase Transition in the Layered Pnictide Oxide Superconductor
Yamamoto T., Li Zhi, Kawakami T., Yajima T., Nakano K., Tohyama T., Okada T., Yagi T., Kikegawa T., Kobayashi Y., Kageyama H.
Meeting Abstracts of the Physical Society of Japan 70 2013 - 2013 2015
-
18pCD-9 A Magnetically Ordered LiNbO_3-type Manganese Oxynitride
Tassel C., Kuno Y., Yamamoto T., Kobayashi Y., Kageyama H.
Meeting Abstracts of the Physical Society of Japan 70 2020 - 2020 2015
-
Y. Mukai, H. Hirori, T. Yamamoto, H. Kageyama, K. Tanaka
Ultrafast Phenomena XIX 162 649 - 652 2015
-
22aCP-4 Nonlinear Terahertz Magnetization Dynamics of Rare-earth Ferrite HoFeO_3
Mukai Y., Hirori H., Yamamoto T., Kageyama H., Tanaka K.
Meeting Abstracts of the Physical Society of Japan 70 1494 - 1494 2015
-
Superconductivity in LaPd2As2 with a collapsed 122 structure Reviewed
Subodh Ganesanpotti, Takeshi Yajima, Kousuke Nakano, Yasumasa Nozaki, Takafumi Yamamoto, Cedric Tassel, Yoji Kobayashi, Hiroshi Kageyama
JOURNAL OF ALLOYS AND COMPOUNDS 613 370 - 374 2014.11
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Y. Mukai, H. Hirori, T. Yamamoto, H. Kageyama, K. Tanaka
APPLIED PHYSICS LETTERS 105 ( 2 ) 2014.7
-
29pCG-14 Pressure-induced Charge Transfer Transition in a Square Planar Iron Oxide Reviewed
Yamamoto T., Kawakami T., Mizumaki M., Yoshii R., Okada T., Yagi T., Kobayashi Y., Takano M., Kageyama H.
Meeting abstracts of the Physical Society of Japan 69 ( 1 ) 657 - 657 2014.1
-
Substrate-induced anion rearrangement in epitaxial thin films of LaSrCoO4-xHx Reviewed
Guillaume Bouilly, Takeshi Yajima, Takahito Terashima, Yoshiro Kususe, Koji Fujita, Cedric Tassel, Takafumi Yamamoto, Katsuhisa Tanaka, Yoji Kobayashi, Hiroshi Kageyama
CRYSTENGCOMM 16 ( 41 ) 9669 - 9674 2014
-
Field-induced ferromagnetism of Fe4+-perovskite system, Sr 1-xBaxFeO3(0≤x≤1) Reviewed
Naoaki Hayashi, Takafumi Yamamoto, Atsushi Kitada, Akira Matsuo, Koichi Kindo, James Hester, Hiroshi Kageyama, Mikio Takano
Journal of the Physical Society of Japan 82 ( 11 ) 2013.11
-
Gas phase contributions to topochemical hydride reduction reactions Reviewed
Yoji Kobayashi, Zhaofei Li, Kei Hirai, Cedric Tassel, Francois Loyer, Noriya Ichikawa, Naoyuki Abe, Takafumi Yamamoto, Yuichi Shimakawa, Kazuyoshi Yoshimura, Mikio Takano, Olivier J. Hernandez, Hiroshi Kageyama
JOURNAL OF SOLID STATE CHEMISTRY 207 190 - 193 2013.11
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Hydride Reductions of Transition Metal Oxides Reviewed
Takafumi Yamamoto, Hiroshi Kageyama
CHEMISTRY LETTERS 42 ( 9 ) 946 - 953 2013.9
-
Novel Superconductor BaTi_2Bi_2O with a d^1 Square Lattice Reviewed
Yajima Takeshi, Nakano Kousuke, Takeiri Fumitaka, Hester James, Yamamoto Takafumi, Kobayashi Yoji, Tsuji Naruki, Kim Jungeun, Fujiwara Akihiko, Kageyama Hiroshi
Meeting abstracts of the Physical Society of Japan 68 ( 2 ) 563 - 563 2013.1
-
Takeshi Yajima, Kousuke Nakano, Fumitaka Takeiri, James Hester, Takafumi Yamamoto, Yoji Kobayashi, Naruki Tsuji, Jungeun Kim, Akihiko Fujiwara, Hiroshi Kageyama
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 82 ( 1 ) 2013.1
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Yaguchi Junta, Kawakami Takateru, Yamamoto Takafumi, Kobayashi Youji, Kageyama Hiroshi
Meeting abstracts of the Physical Society of Japan 68 ( 2 ) 393 - 393 2013.1
-
Magnon generation in rare-earth orthoferrite HoFeO_3 by intense terahertz magnetic field Reviewed
Mukai Y., Hirori H., Yamamoto T., Kageyama H., Tanaka K.
Meeting abstracts of the Physical Society of Japan 68 ( 2 ) 691 - 691 2013.1
-
Solventless Low Temperature Reactions for Novel Transition Metal Oxides Reviewed
33 ( 1 ) 51 - 56 2013.1
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Oxyhydrides of (Ca,Sr,Ba)TiO3 Perovskite Solid Solutions Reviewed
Tatsunori Sakaguchi, Yoji Kobayashi, Takeshi Yajima, Masatoshi Ohkura, Cedric Tassel, Fumitaka Takeiri, Shingo Mitsuoka, Hiroshi Ohkubo, Takafumi Yamamoto, Jung Eun Kim, Naruki Tsuji, Akihiko Fujihara, Yoshitaka Matsushita, James Hester, Maxim Avdeev, Kenji Ohoyama, Hiroshi Kageyama
INORGANIC CHEMISTRY 51 ( 21 ) 11371 - 11376 2012.11
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(Sr1-xBax)FeO2 (0.4 <= x <= 1): A New Oxygen-Deficient Perovskite Structure Reviewed
Takafumi Yamamoto, Yoji Kobayashi, Naoaki Hayashi, Cedric Tassel, Takashi Saito, Shoji Yamanaka, Mikio Takano, Kenji Ohoyama, Yuichi Shimakawa, Kazuyoshi Yoshimura, Hiroshi Kageyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 134 ( 28 ) 11444 - 11454 2012.7
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20pCD-10 Mossbauer of Sr_<0.7>Eu_<0.3>FeO_2 under high pressure Reviewed
Ishii Minoru, Kawakami Takateru, Yamamoto Takafumi, Kobayashi Youji, Kageyama Hiroshi
Meeting abstracts of the Physical Society of Japan 67 ( 2 ) 437 - 437 2012.1
-
Quadruple-layered perovskite (CuCl)Ca2NaNb4O13 Reviewed
A. Kitada, Y. Tsujimoto, T. Yamamoto, Y. Kobayashi, Y. Narumi, K. Kindo, A. A. Aczel, G. M. Luke, Y. J. Uemura, Y. Kiuchi, Y. Ueda, K. Yoshimura, Y. Ajiro, H. Kageyama
JOURNAL OF SOLID STATE CHEMISTRY 185 10 - 17 2012.1
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<Research Report>Synthesis, Structure and physical properties of (Sr, Ba)FeO2 Reviewed
0 ( 19 ) 3 - 11 2011.12
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Random fan-out state induced by site-random interlayer couplings Reviewed
Ryo Tamura, Naoki Kawashima, Takafumi Yamamoto, Cedric Tassel, Hiroshi Kageyama
PHYSICAL REVIEW B 84 ( 21 ) 2011.12
-
B1-to-B2 Structural Transitions in Rock Salt Intergrowth Structures Reviewed
Takafumi Yamamoto, Yoji Kobayashi, Taku Okada, Takehiko Yagi, Takateru Kawakami, Cedric Tassel, Shota Kawasaki, Naoyuki Abe, Ken Niwa, Takumi Kikegawa, Naohisa Hirao, Mikio Takano, Hiroshi Kageyama
INORGANIC CHEMISTRY 50 ( 22 ) 11787 - 11794 2011.11
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Fe-Site Substitution Effect on the Structural and Magnetic Properties in SrFeO2 Reviewed
Liis Seinberg, Takafumi Yamamoto, Cedric Tassel, Yoji Kobayashi, Naoaki Hayashi, Atsushi Kitada, Yuji Sumida, Takashi Watanabe, Masakazu Nishi, Kenji Ohoyama, Kazuyoshi Yoshimura, Mikio Takano, Werner Paulus, Hiroshi Kageyama
INORGANIC CHEMISTRY 50 ( 9 ) 3988 - 3995 2011.5
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Pressure-Induced Structural, Magnetic, and Transport Transitions in the Two-Legged Ladder Sr3Fe2O5 Reviewed
Takafumi Yamamoto, Cedric Tassel, Yoji Kobayashi, Takateru Kawakami, Taku Okada, Takehiko Yagi, Hideto Yoshida, Takanori Kamatani, Yoshitaka Watanabe, Takumi Kikegawa, Mikio Takano, Kazuyoshi Yoshimura, Hiroshi Kageyama
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 133 ( 15 ) 6036 - 6043 2011.4
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BaFeO3: A Ferromagnetic Iron Oxide Reviewed
Naoaki Hayashi, Takafumi Yamamoto, Hiroshi Kageyama, Masakazu Nishi, Yoshitaka Watanabe, Takateru Kawakami, Yoshitaka Matsushita, Atsushi Fujimori, Mikio Takano
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 50 ( 52 ) 12547 - 12550 2011
-
Spin transition of Sr_3Fe_2O_5 under high pressure Reviewed
YOSHIDA Hideto, KAWAKAMI Takateru, KAMATANI Takanori, KAGEYAMA Hiroshi, YAMAMOTO Takafumi, TASSEL Cedric, NASU Saburo
51 121 - 121 2010.10
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24pWL-13 Super Solid Phase by Effect of Anisotropic Randomness and Frustration Reviewed
Tamura Ryo, Kawashima Naoki, Seinberg Liis, Yamamoto Takafumi, Kageyama Hiroshi
Meeting abstracts of the Physical Society of Japan 65 ( 2 ) 388 - 388 2010.8
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25aPS-72 High-Pressure Mossbauer spectroscopy of Sr_3Fe_2O_5 under external field Reviewed
Yoshida Hideto, Kawakami Takateru, Kamatani Takanori, Kageyama Hiroshi, Yamamoto Takafumi, Tassel Cedric, Nasu Saburo
Meeting abstracts of the Physical Society of Japan 65 ( 2 ) 415 - 415 2010.8
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Synthesis and Thermal Stability of the Solid Solution AFeO(2) (A = Ba, Sr, Ca) Reviewed
Takafumi Yamamoto, Zhaofei Li, Cedric Tassel, Naoaki Hayashi, Mikio Takano, Masahiko Isobe, Yutaka Ueda, Kenji Ohoyama, Kazuyoshi Yoshimura, Yoji Kobayashi, Hiroshi Kageyama
INORGANIC CHEMISTRY 49 ( 13 ) 5957 - 5962 2010.7
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Y. J. Uemura, A. A. Aczel, Y. Ajiro, J. P. Carlo, T. Goko, D. A. Goldfeld, A. Kitada, G. M. Luke, G. J. MacDougall, I. G. Mihailescu, J. A. Rodriguez, P. L. Russo, Y. Tsujimoto, C. R. Wiebe, T. J. Williams, T. Yamamoto, K. Yoshimura, H. Kageyama
PHYSICAL REVIEW B 80 ( 17 ) 2009.11
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T. Goko, A. A. Aczel, E. Baggio-Saitovitch, S. L. Bud'ko, P. C. Canfield, J. P. Carlo, G. F. Chen, Pengcheng Dai, A. C. Hamann, W. Z. Hu, H. Kageyama, G. M. Luke, J. L. Luo, B. Nachumi, N. Ni, D. Reznik, D. R. Sanchez-Candela, A. T. Savici, K. J. Sikes, N. L. Wang, C. R. Wiebe, T. J. Williams, T. Yamamoto, W. Yu, Y. J. Uemura
PHYSICAL REVIEW B 80 ( 2 ) 2009.7
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Synthesis and magnetism of SrFe1-xMxO2 (M=Co,Mn) obtained by low temperature solid state reduction
Sumida Yuji, Kitada Atsushi, Yoshimura Kazuyoshi, Yamamoto Takahumi, Watanabe Takashi, Liss Seinberg, Cedric Tassel, Nishi Masakazu, Kageyama Hiroshi, Hayashi Naoaki, Tuzimoto Yoshihiro
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2009 ( 0 ) 2G08 - 2G08 2009
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Synthesis and Structural Phase Transition of the Infinite-Layer Iron Oxide (Sr1-xBax)FeO2
Yamamoto Takafumi, Shimakawa Yuichi, Yoshimura Kazuyoshi, Saito Takashi, Kageyama Hiroshi, Hayashi Naoaki, Takano Mikio, Tassel Cédric, Tsujimoto Yoshihiro, Kitada Atsushi, Oyama Kenji
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2009 ( 0 ) 364 - 364 2009
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A Structural Investigation of the Infinite Layer Sr1-xCaxFeO2 (0 ≤ x ≤ 1)
Tassel Cedric, Kageyama Hiroshi, Yamamoto Takafumi, Kitada Atsushi, Tsujimoto Yoshihiro, Matsushita Yoshitaka, Katsuya Yoshio, Tanaka Masahiko, Yoshimura Kazuyoshi
Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan 2009 ( 0 ) 2PG06 - 2PG06 2009
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Y. Tsujimoto, H. Kageyama, Y. Baba, A. Kitada, T. Yamamoto, Y. Narumi, K. Kindo, M. Nishi, J. P. Carlo, A. A. Aczel, T. J. Williams, T. Goko, G. M. Luke, Y. J. Uemura, Y. Ueda, Y. Ajiro, K. Yoshimura
PHYSICAL REVIEW B 78 ( 21 ) 214410 2008.12
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Y. Tsujimoto, H. Kageyama, Y. Baba, A. Kitada, T. Yamamoto, Y. Narumi, K. Kindo, M. Nishi, J. P. Carlo, A. A. Aczel, T. J. Williams, T. Goko, G. M. Luke, Y. J. Uemura, Y. Ueda, Y. Ajiro, K. Yoshimura
PHYSICAL REVIEW B 78 ( 21 ) 2008.12
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Stability of the infinite layer structure with iron square planar coordination Reviewed
Cedric Tassel, Takashi Watanabe, Yoshihiro Tsujimoto, Naoaki Hayashi, Atsushi Kitada, Yuji Sumida, Takafumi Yamamoto, Hiroshi Kageyama, Mikio Takano, Kazuyoshi Yoshimura
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 130 ( 12 ) 3764 - + 2008.3
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金属ハイドライド還元法による鉄酸化物の合成 Reviewed
陰山洋, セドリック・タッセル, 辻本吉廣, 山本隆文, 渡邉貴志, 吉村一良
機能材料 28 60 - 66 2008
MISC
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Advanced analysis of the reaction in SrCrO3-δ by time-resolved XRD and Bayesian inference
小菅大輝, 河口彰吾, 小林慎太郎, 横山優一, 水牧仁一朗, 細川三郎, 東正樹, 東正樹, 山本隆文
日本セラミックス協会秋季シンポジウム講演予稿集(Web) 36th 2023
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Time-resolved XRD measurement of topochemical reaction in Sr3Fe2O7-δ
山本隆文, 菅井玲, 小菅大輝, 東正樹, 河口彰吾, 別府孝介, 細川三郎
日本セラミックス協会秋季シンポジウム講演予稿集(Web) 35th 2022
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Observation of topochemical reaction in SrCrO3-δ by time-resolved XRD
小菅大輝, 河口彰吾, 別府孝介, 細川三郎, 東正樹, 山本隆文
日本セラミックス協会秋季シンポジウム講演予稿集(Web) 35th 2022
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High-Pressure Synthesis of A2NiO2Ag2Se2 (A=Sr, Ba) with a High-Spin Ni2+ in Square-Planar Coordination
Matsumoto Yuki, Yamamoto Takafumi, Nakano Kousuke, Takatsu Hiroshi, Murakami Taito, Hongo Kenta, Hongo Kenta, Hongo Kenta, Hongo Kenta, Hongo Kenta, Maezono Ryo, Maezono Ryo, Ogino Hiraku, Song Dongjoon, Brown Craig M., Tassel Cedric, Kageyama Hiroshi
Angewandte Chemie 131 ( 3 ) 2019
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金属秩序NiAs型構造を持つ新規ニクタイドの合成と物性
村上泰斗, 山本隆文, 陰山洋
日本化学会春季年会講演予稿集(CD-ROM) 98th 2018
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六方晶系BaVO3-xHxにおける水酸化物イオンのサイト選択性に関する第一原理計算
設樂一希, 山本隆文, 陰山洋, 森分博紀, 桑原彰秀
日本セラミックス協会年会講演予稿集(CD-ROM) 2018 2018
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層状秩序NiAs型構造を持つ新規ニクタイドの合成と物性
村上泰斗, 山本隆文, 陰山洋
日本セラミックス協会年会講演予稿集(CD-ROM) 2018 2018
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In‐situ抵抗測定によるSrTiO3への水素イオンビーム照射効果の研究
中山亮, 前里光彦, 吉宗航, 山本隆文, 陰山洋, 寺嶋孝仁, 北川宏
京都大学物性科学センター誌 ( 30 ) 46 2017.6
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竹入史隆, 山本隆文, 細川三郎, 林直顕, 池田一貴, 本田孝志, 大友季哉, TASSEL Cedric, 小林洋治, 陰山洋
日本化学会春季年会講演予稿集(CD-ROM) 97th ROMBUNNO.3G1‐18 2017.3
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中山亮, 前里光彦, 吉宗航, 山本隆文, 陰山洋, 寺嶋孝仁, 北川宏
日本化学会春季年会講演予稿集(CD-ROM) 97th ROMBUNNO.2G1‐10 2017.3
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松本勇輝, 山本隆文, 竹入史隆, 陰山洋, 林直顕, 遠山貴己, ZHI Li
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 29th ROMBUNNO.2H17 - 2192 2016.8
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竹入史隆, 山本隆文, 藤田晃司, 細川三郎, 小林洋治, 陰山洋, 林直顕, 池田一貴, 本田孝志, 大友季哉
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 29th ROMBUNNO.1H20 2016.8
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山本隆文, 松本勇輝, 竹入史隆, LI Zhi, 林直顕, 遠山貴己, 陰山洋
日本物理学会講演概要集(CD-ROM) 71 ( 1 ) ROMBUNNO.21ABN‐6 - 2192 2016.3
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三木田梨歩, 阿波連知子, 山本隆文, 竹入史隆, 吉宗航, 藤田晃司, 吉田傑, 田中勝久, BATUK Dmitry, ABAKUMOV Artem M, ABAKUMOV Artem M, BROWN Craig M, 小林洋治, 小林洋治, 陰山洋, 陰山洋
日本化学会春季年会講演予稿集(CD-ROM) 96th ROMBUNNO.2D5‐17 2016.3
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松本勇輝, 山本隆文, 竹入史隆, 林直顕, 陰山洋, ZHI Li, 遠山貴己
日本化学会春季年会講演予稿集(CD-ROM) 96th ROMBUNNO.2D5‐14 2016.3
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竹入史隆, 會津康平, 三木田梨歩, 山本隆文, 小林洋治, 陰山洋, 矢島健
日本セラミックス協会年会講演予稿集(CD-ROM) 2016 ROMBUNNO.1E24 2016.3
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新規層状アンチモナイドの合成と磁気物性
村上泰斗, 山本隆文, TASSEL Cedric, 高津浩, 陰山洋
日本セラミックス協会年会講演予稿集(CD-ROM) 2016 2016
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新規層状アンチモン化物の合成と磁気物性
村上泰斗, 山本隆文, TASSEL Cedric, 高津浩, 陰山洋
日本物理学会講演概要集(CD-ROM) 71 ( 1 ) 2016
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金属秩序NiAs型構造を持つ磁性体HfMnSb2の次元性制御
村上泰斗, 山本隆文, 高津浩, 陰山洋, YUSUF S.M.
日本物理学会講演概要集(CD-ROM) 71 ( 2 ) 2016
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金属秩序NiAs型構造を持つ磁性体HfMnSb2の次元性制御
村上泰斗, 山本隆文, 高津浩, 陰山洋, YUSUF S.M.
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 29th 2016
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出雲菜々, 山本隆文, 竹入史隆, 陰山洋
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 28th ROMBUNNO.3F03 2015.9
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三木田梨歩, 阿波連知子, 山本隆文, 竹入史隆, 吉宗航, 藤田晃司, 田中勝久, 陰山洋
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 28th ROMBUNNO.3F06 2015.9
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竹入史隆, 矢島健, 吉宗航, 山本隆文, 小林洋治, 陰山洋
京都大学低温物質科学研究センター誌 ( 26 ) 71 2015.6
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竹入史隆, 會津康平, 吉宗航, 藤田晃司, 田中勝久, 山本隆文, 小林洋治, 陰山洋, 矢島健, 赤松寛文, LEI Shiming, GOPALAN Venkatraman
日本セラミックス協会年会講演予稿集(CD-ROM) 2015 ROMBUNNO.2H02 2015.3
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竹入史隆, 會津康平, 吉宗航, 山本隆文, 小林洋治, 陰山洋, 矢島健
日本セラミックス協会年会講演予稿集(CD-ROM) 2015 ROMBUNNO.2H01 2015.3
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9pAD-11 Nonlinear terahertz spin dynamics in rare-earth orthoferrite HoFeO_3
Mukai Y., Hirori H., Yamamoto T., Kageyama H., Tanaka K.
Meeting abstracts of the Physical Society of Japan 69 ( 2 ) 529 - 529 2014.8
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9aBC-7 High spin - intermediate spin transition of Sr_<0.7>Eu_<0.3>FeO_2
Yamaguchi Junta, Kawakami Takateru, Yamamoto Takafumi, Kobayashi Youji, Kageyama Hiroshi, Kawamura Naomi, Mizumaki Masaichiro
Meeting abstracts of the Physical Society of Japan 69 ( 2 ) 301 - 301 2014.8
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ビスマス化物新規超伝導物質の探索
村上泰斗, 山本隆文, 吉宗航, 中野晃佑, 陰山洋
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 27th 2014
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トポケミカル酸化反応による新規ペロブスカイト薄膜の合成
吉宗航, TASSEL Cedric, BOUILLY Guillaume, 寺嶋孝仁, 山本隆文, 小林洋冶, 陰山洋
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 27th 2014
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新規層状ニクタイド水素化物の合成
野崎保将, 矢島健, 矢島健, 吉宗航, 後藤能宏, TASSEL Cedric, 山本隆文, 小林洋治, 陰山洋
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 27th 2014
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新超伝導体BaTi2Bi2OおよびBaTi2Pn2O(Pn=As,Sb,Bi)の電子相図
矢島健, 中野晃佑, 竹入史隆, 野崎保将, HESTER James, 山本隆文, 辻成希, KIM Jungeun, 藤原明比古, 小林洋治, 陰山洋
応用物理学会秋季学術講演会講演予稿集(CD-ROM) 74th ROMBUNNO.17P-C8-5 2013.8
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アニオン固溶系BaTi2Pn2O(Pn=As,Sb,Bi)の超伝導物性
野崎保将, 矢島健, 中野晃佑, 竹入史隆, 山本隆文, 小林洋治, 陰山洋, 藤原明比古, KIM Jungeun, 辻成希, HESTER James
日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 26th ROMBUNNO.2N21 2013.8
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新規チタン酸水素化物(2):(Ca,Sr,Ba)TiO3-xHx
坂口辰徳, 矢島健, 小林洋治, 大倉仁寿, 竹入史隆, 光岡新悟, 大久保博史, 山本隆文, HESTER James, ANDEEV Maxim, 大山研司, 陰山洋
日本セラミックス協会年会講演予稿集 2012 166 2012.3
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25pTE-12 Phase Transitions of Site-Random Model with Anisotropic Interactions Reviewed
Tamura Ryo, Kawashima Naoki, Seinberg Luis, Yamamoto Takafumi, Kageyama Hiroshi
Meeting abstracts of the Physical Society of Japan 66 ( 1 ) 295 - 295 2011.3
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25aPS-17 Mossbauer spectroscopy for SrFe_<0.8>Mn_<0.2>O_2 under high pressure Reviewed
Watanabe Yoshitaka, Kawakami Takateru, Nakakura Yuta, Yamamoto Takahumi, Kageyama Hiroshi, Takano Mikio
Meeting abstracts of the Physical Society of Japan 66 ( 1 ) 459 - 459 2011.3
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Li2MnO3系正極材料の酸素不定比性と電子・局所構造解析
大石昌嗣, 川村渥史, 折笠有基, 藤本貴洋, 高梨優, 山本隆文, 小林洋治, 陰山洋, 谷田肇, 荒井創, 石井秀司, 渡邊巌, 太田俊明, 内本喜晴, 内本喜晴, 小久見善八
固体イオニクス討論会講演要旨集 37th 2011
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23aGC-4 Mossbauer spectroscopy of Sr_3Fe_2O_5 under high pressure
Yoshida Hideto, Kawakami Takateru, Kageyama Hiroshi, Yamamoto Takafumi, Tassel Cedric, Yoshimura Kazuyoshi, Nasu Saburo
Meeting abstracts of the Physical Society of Japan 65 ( 1 ) 514 - 514 2010.3
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27pRE-10 Frustrated Magnetism in Co- and Mn-Substituted Infinite Layer Iron Oxide SrFeO_2
Yamamoto T., Sumida Y., Seimberg Liis, Kageyama H., Watanabe T., Tassel Cedric, Nishi M., Hayashi N., Tsujimoto Y., Kitada A., Yoshimura K.
Meeting abstracts of the Physical Society of Japan 64 ( 2 ) 379 - 379 2009.8
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26aRA-6 Mossbauer Effect of Sr_<1-x>Ca_xFeO_2
Hayashi Naoaki, Yamamoto Takafumi, Tassel Cedric, Tsujimoto Yoshinori, Kageyama Hiroshi, Yoshimura Kazuyoshi, Takano Mikio
Meeting abstracts of the Physical Society of Japan 64 ( 2 ) 357 - 357 2009.8
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27aQJ-2 Synthesis and Magnetism of Two-Dimensional Quantum Spin System (CuCl)Ca_2NaNb_4O_<13>
Kitada A., Kageyama H., Tsujimoto Y., Yamamoto T., Ajiro Y., Narumi Y., Kindo K., Nishi M., Kiuchi Y., Ichihara M., Ueda Y., Uemura Y. J., Yoshimura K.
Meeting abstracts of the Physical Society of Japan 64 ( 2 ) 366 - 366 2009.8
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28aTH-11 Synthesis, structure and magnetism of BaFeO_2
Yamamoto T., Saito T., Kageyama H., Hayashi N., Takano M., Tassel Cedric, Tsujimoto Y., Kitada A., Oyama K., Shimakawa Y., Yoshimura K.
Meeting abstracts of the Physical Society of Japan 64 ( 1 ) 478 - 478 2009.3
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30aTC-8 μSRで見た鉄砒素超伝導体の磁性と超伝導(30aTC 鉄砒素超伝導体5(中性子,NMR),領域8(強相関系:高温超伝導,強相関f電子系など))
後神 達郎, Carlo J. P., Aczel A. A., Williams T. J., Yu W., Luke G. M., Sanchez-Candela D. R., Baggio-Saitovitch E., 山本 隆文, 陰山 洋, Ni N., Bud'ko S. L., Canfield P. C., Chen G. F., Wang N. L., Dai Pengcheng, Uemura Y. J.
日本物理学会講演概要集 64 ( 1 ) 649 - 649 2009.3
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29pTG-6 Characterization of Two-Dimensional Spin System (CrCl)LaNb_2O_7
Kitada A., Tsujimoto Y., Watanabe T., Yamamoto T., Kageyama H., Ajiro Y., Yoshimura K., Nishi M.
Meeting abstracts of the Physical Society of Japan 64 ( 1 ) 508 - 508 2009.3
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20pQG-6 Synthesis and structural phase transition of the infinite-layer iron oxide Sr_<1-x>Ba_xFeO_2
Yamamoto T., Saito T., Kageyama H., Hayashi N., Takano M., Tassel Cedric, Tsujimoto Y., Shimakawa Y., Yoshimura K.
Meeting abstracts of the Physical Society of Japan 63 ( 2 ) 364 - 364 2008.8
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23aPS-68 Synthesis of Infinite-Layer Iron Oxides: Sr_<1-x>Ba_xFeO_2
Yamamoto T., Tsujimoto Y., Tassel C., Watanabe T., Kageyama H., Yoshimura K.
Meeting abstracts of the Physical Society of Japan 63 ( 1 ) 441 - 441 2008.2
Research Projects
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オプトエレクトロニック応用に向けた省エネルギー無毒性層状ペロブスカイト開発
Grant number：24KF0147 2024.10 - 2027.3
日本学術振興会 科学研究費助成事業 特別研究員奨励費
山本 隆文
Grant amount：\2000000 （ Direct Cost: \2000000 ）
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Exploring physicochemical properties of Supra-ceramics
Grant number：22H05147 2022.6 - 2027.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Transformative Research Areas (A)
Grant amount：\176280000 （ Direct Cost: \135600000 、 Indirect Cost：\40680000 ）
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特異なアニオン欠損面を持つ新規ペロブスカイトの開拓
Grant number：23K23035 2022.4 - 2025.3
日本学術振興会 科学研究費助成事業 基盤研究(B)
山本 隆文, 松井 直喜, 池澤 篤憲
Grant amount：\17420000 （ Direct Cost: \13400000 、 Indirect Cost：\4020000 ）
アニオン欠損を酸化物に導入することは電気伝導性や磁性などの物性の変化をもたらし、またイオン伝導性や触媒活性といった様々な機能性の獲得をもたらす。アニオン欠損の研究は特にペロブスカイト酸化物ABO3 (A,Bは金属イオン)において盛んに行われている。本研究では、八面体を好む金属と四面体を好む金属を合理的に組み合わせることでアニオン欠損構造を持つペロブスカイト物質の合成と新規物質探索を行うことを目的とする。特に、これまで開拓があまり進んでいない、(111)p面欠損を持つペロブスカイトに特に注目して、新規物質の合成や物性開拓を進めている。
R5年度は、(111)p面欠損を持つ新規酸素欠損ペロブスカイト酸化物Ba6Ta2Na2X2O17 (X = P, V)をInorganic Chemstry誌に報告した。直前にNature誌（Szymanski et al. Nature 2023, 624, 86-91.）に報告された構造解析の誤りを正すもので、学術的に重要な結果であると考えている。また、酸素欠陥秩序を持つSr3Fe2O7-dの酸素放出挙動の反応過程の可視化の論文をAdv. Sci.誌に報告した。さらに超高圧フラックス法を用いた酸水素化物ペロブスカイトの合成の論文をJ. Am. Chem. Soc.誌に報告するなど、多くのアウトプットを行った。 -
特異なアニオン欠損面を持つ新規ペロブスカイトの開拓
Grant number：22H01767 2022.4 - 2025.3
日本学術振興会 科学研究費助成事業 基盤研究(B)
山本 隆文, 松井 直喜, 池澤 篤憲
Grant amount：\17420000 （ Direct Cost: \13400000 、 Indirect Cost：\4020000 ）
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Synthesis of layered compounds based on differences in compressibility
Grant number：19K22230 2019.6 - 2022.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)
Takafumi Yamamoto
Grant amount：\6240000 （ Direct Cost: \4800000 、 Indirect Cost：\1440000 ）
In recent years, the synthesis of inorganic compounds using pressures above 1 GPa has become common, but there are no clear guidelines as to what kind of compounds can be synthesized at high pressures. In this study, we focused on the parameter of ionic compressibility (i.e., hardness/softness) to clarify the behavior of compounds under high pressure and their stable structures. Specifically, we focused on the softness of pnictides and hydrides compared to oxide ions, and clarified phase transitions and synthesis methods under high pressure in mixed anionic compounds.
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Summary of Synthesis of Mixed Anion Compounds toward Novel Functionalities
Grant number：16H06438 2016.6 - 2021.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
Kageyama Hiroshi
Grant amount：\182130000 （ Direct Cost: \140100000 、 Indirect Cost：\42030000 ）
Under our leadership with the advice of the evaluation committee, all the members gathered their strengths and managed the project in a functional and dynamic manner. Collaboration has been accelerated and strengthened with the addition of new members who are capable of carrying out new collaborations, and collaborative research covering a wider range of fields has become possible. The website introduced not only research results but also outreach activities, and the human resources database and research database were also put into full-scale operation. Under the collaboration with the overseas activities support group, mutual exchanges with overseas researchers, use of large overseas facilities, international conferences, and an online seminar series after the covid were held. In addition, the group led research both domestically and internationally through a review paper (Nat Commun 2018) andt textbook on mixed-anion compounds (2021), and the planning of various symposia.
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Understanding of Mixed Anion Compounds: Analyses of Chemical, Structural and Electronic States
Grant number：16H06440 2016.6 - 2021.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
Hayashi Katsuro
Grant amount：\275080000 （ Direct Cost: \211600000 、 Indirect Cost：\63480000 ）
For the evaluation of “mixed anion compounds”, the conventional research style has not been applicable and the evaluation and analysis methods had not been established at all. To overcome this, leading researchers about advanced material evaluation have collaborated with each other as well as with research groups of the synthesis and the materials functions. Regarding issues on the evaluation and characteristics of mixed anion compounds, the first half of the project focused on the methodology of light-element anion identification and relevant structural analysis, the clarification of the specificity of hydride (H-) ions, and the clarification of coordination polyhedral geometry through joint experimental and theoretical researches. After that, we focused on the dynamics of mixed anion systems, expanded to the analysis and understanding of materials systems and processes beyond crystals, and finally elaborated on the exploration and theoretical analysis of new ionic conductors.
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Structure and Physical property design by high compressibility of hydride ion
Grant number：16H06033 2016.4 - 2020.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A)
Yamamoto Takafumi
Grant amount：\25480000 （ Direct Cost: \19600000 、 Indirect Cost：\5880000 ）
We reveal two properties of hydride anion by high pressure experiments of vanadium oxyhydrides Srn+1VnO2n+1Hn (n = 1,2,∞). 1) Hydride anion can act as phi-blockers” in inorganic solids: hydride anion effectively blocks exchange pathways of phi-symmetry even under extremely high pressure due to lack of p orbital in hydride anion. 2) hydride anion is extraordinarily compressible compared with oxide anion. These concepts provide a strong motivation for the synthesis of new oxyhydride phases with novel properties.
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Selective Intercalation Chemistry of Layered Inorganic Compounds
Grant number：16H02267 2016.4 - 2019.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
Hiroshi Kageyama
Grant amount：\46540000 （ Direct Cost: \35800000 、 Indirect Cost：\10740000 ）
In this study, we have discovered a novel phenomenon in which only the metal that selects tetrahedral coordination such as Cd is selected for the layered substance Ti2PTe2 selectively and at low temperature in the solid phase, and a similar experiment is performed for the Zr-substituted Zr2PTe2. The same tendency as Ti2PTe2, that is, selective metals of only Zn, Cu and Cd were revealed. In general, anomalous intercalation phenomenon becomes common to substances with the same structure, and the key to these properties is that Ti and Zr is coordinated by P3 and Te3 anions (mixed-anion coordination) was revealed. We also succeeded in promoting the low temperature anion exchange reaction in oxides using this finding.
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Synthesis and characterization of extremely low valent iron
Grant number：26620044 2014.4 - 2017.3
Japan Society for the Promotion of Science Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
Takafumi Yamamoto
Grant amount：\4030000 （ Direct Cost: \3100000 、 Indirect Cost：\930000 ）
In this research, we explored extremely low valent iron. We demonstrated that (Sr0.7Eu0.3)FeO2 shows a intersite charge transfer transition, which read mnovalent iron. Around the intersite charge transfer transition, we found that the compound exhibits interesting phenomena, such as a spin transition, an inslator-to-metal transition, a magnetic transition, and a spin flop transition. This indicate that extremely low valent iron can be interesting playground for searching exotic phenomena. In addition, we synthesized new compounds, lanthanoid-substituted SrFeO2 and BaFe2Se2O.
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平面四配位鉄酸化物の金属化・強磁性体化
Grant number：25889037 2013.8 - 2015.3
日本学術振興会 科学研究費助成事業 研究活動スタート支援
山本 隆文
Grant amount：\2730000 （ Direct Cost: \2100000 、 Indirect Cost：\630000 ）
本研究では、元素置換などによって平面四配位鉄酸化物を強磁性体・金属化することを目的とした研究である。代表者は申請書に掲げるSrFeO2のSrサイトを希土類元素で置換を行った。Nd,Sm,Ho置換SrFeO2では、得られた試料の組成が(Sr1-xLnx)Fe2+O2+x/2のようになり、余剰の酸素が希土類を置換した分だけ無限層の層間に挿入されていることが分かった。これにより、期待したようなキャリアドープはできていないことが分かった。またEu置換体においては余剰酸素はなかったもののEuが三価でなく二価で固溶することによってやはり絶縁体となった。(Sr2+0.7Eu2+0.3)Fe2+O2に高圧をかけるとEu2+からFe2+へ電荷移動を起こし、鉄の価数が1.7価（一価と二価の混合原子価）となることが分かってきた。またこの時室温付近で強磁性の金属となった。Euを固溶していないSrFeO2も高圧下で金属強磁性化するが、SrFeO2だと金属強磁性化する転移圧力が33GPaであったのに対してEu30%置換体では大幅に下がり15GPaとなった。このことは平面四配位鉄酸化物の金属化と強磁性化を常圧で実現するうえで重要なステップとなると考えられる。また計画書に示すようにSrFeO2へのアルカリ金属置換と4d,5d遷移金属置換にもトライしたが、現時点では目的の平面四配位鉄酸化物の合成成功には至っていない。