Seeking for the electronic-structure origin of the unusual spin states in trivalent Co oxides
| Project/Area Number |
17K05502
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
Saitoh Tomohiko 東京理科大学, 理学部第一部応用物理学科, 教授 (30311129)
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| Co-Investigator(Kenkyū-buntansha) |
小林 義彦 東京医科大学, 医学部, 講師 (60293122)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | コバルト酸化物 / 電子構造 / 光電子分光 / スピンクロスオーバー / バンド計算 / 強相関電子系 / 遷移金属酸化物 / 磁性 / コンプトン散乱 / 低スピン / 高スピン / Co酸化物 / スピン状態 / 電子状態 |
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| Outline of Final Research Achievements |
We measured the electronic structure of perovskite-type Co oxides RCoO3 (R: rare earth) from the room temperature (RT) down to about 10 K by using hard x-ray photoemission spectroscopy (HAXPES). In particular, we have succeeded in the lowest-temperature measurements for the first time, which had never been done because of experimental difficulties. From our analysis, we found that (1) the temperature-dependent changes in the electronic structure of LaCoO3 cannot be explained by a superposition of the low-spin and the high-spin state (2) the electronic states that have not been seriously considered, such as Co 4sp and La 5p states, may contribute to the temperature-dependent changes in the Co 3d spin state. We have also confirmed this uniqueness of LaCoO3 by measuring HAXPES spectra of PrCoO3 from RT down to 20 K to RT, which showed no changes in accordance with its magnetic susceptibility measurement.
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| Academic Significance and Societal Importance of the Research Achievements |
LaCoO3の温度誘起スピンクロスオーバーの解明はノーベル物理学賞受賞のGoodenough博士も好んで追究した、60年以上に亘る未解明問題である。この現象は、Co 3dのスピン状態の温度変化が主な原因とされてきたが、本研究では、Co 3d状態のみを考えてきた従来の考え方に対して、Co 4spやLa 5pなどの別の電子状態も考慮する必要性を指摘した点で学術的意義がある。また、Co酸化物は充電池電極として広く応用されており、その電子構造の解明は、応用の為の基礎知識としても社会的意義がある。
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Report
(4 results)
Research Products
(74 results)
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[Journal Article] Electronic Structure of Sr3Fe2-xCoxO7-d Studied by Photoemission and X-ray Absorption Spectroscopy2020
Author(s)
Rie Naito, Yuta Nakano, Mario Okawa, Hiroki Wadati, Ryouta Nakamura, Jun-ichiro Tozawa, Mitsuru Akaki, Hideki Kuwahara, Takeharu Sugiyama, Eiji Ikenaga, Hiroshi Kumigashira, Enju Sakai, Tomohiko Saitoh
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Journal Title
JPS Conference Proceedings
Volume: 30
Pages: 011073-011073
DOI
Related Report
Peer Reviewed / Open Access
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[Journal Article] Observation of a Pseudogap in the Vicinity of the Metal-Insulator Transition in the Perovskite-type Vanadium Oxides Nd1-xSrxVO32018
Author(s)
Shintaro Yamamoto, Daiki Ootsuki, Daiya Shimonaka, Daisuke Shibata, Kenjiro Kodera, Mario Okawa, Tomohiko Saitoh, Masafumi Horio, Atsushi Fujimori, Hiroshi Kumigashira, Kanta Ono, Eiji Ikenaga, Shigeki Miyasaka, Setsuko Tajima, and Teppei Yoshida
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Journal Title
J. Phys. Soc. Jpn.
Volume: 87
Issue: 2
Pages: 024708-024708
DOI
Related Report
Peer Reviewed
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[Journal Article] Electronic properties of Ba1-xSrxV13O18 (x=0, 0.2, 1) studied using hard x-ray photoemission spectroscopy2017
Author(s)
S. Dash, M. Okawa, T. Kajita, T. Yoshino, R. Shimoyama, K. Takahashi, Y. Takahashi, R. Takayanagi, T. Saitoh, D. Ootsuki, T. Yoshida, E. Ikenaga, N. L. Saini, T. Katsufuji, and T. Mizokawa
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Journal Title
Phys. Rev. B
Volume: 95
Issue: 19
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Presentation] Electronic structure of Pr1-xYxCoO3 showing a unique magnetic state2019
Author(s)
D. Kanai, R. Takayanagi, M. Okawa, Y. Kobayashi, M. Kobayashi, M. Minohara, K. Horiba, H. Kumigashira, A. Yasui, E. Ikenaga, and T. Saitoh
Organizer
The 1st International Workshop on Momentum Microscopy and Spectroscopy for Materials Science
Related Report
Int'l Joint Research
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[Presentation] Electronic structure of Pr1-xYxCoO3 probed by photoemission spectroscopy2018
Author(s)
Daisuke Kanai, Ryohei Takayanagi, Mario Okawa, Yoshihiko Kobayashi, Masaki Kobayashi, Masato Minohara, Koji Horiba, Hiroshi Kumigashira, Akira Yasui, Eiji Ikenaga, and Tomohiko Saitoh
Organizer
International Workshop on Trends in Advanced Spectroscopy in Materials Science (TASPEC)
Related Report
Int'l Joint Research
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[Presentation] Non-Fermi liquid behavior in the vicinity of metal to insulator transition in Nd1-xSrxVO3 probed by photoemission spectroscopy2017
Author(s)
D. Ootsuki, S. Yamamoto, D. Shimonaka, D. Shibata, K. Kodera, M. Okawa, T. Saitoh, M. Horio, A. Fujimori, H. Kumigashira, K. Ono, E. Ikenaga, S. Miyasaka, S. Tajima, and T. Yoshida
Organizer
International Workshop on Strong Correlations and Angle-Resolved Photoemission Spectroscopy 2017 (CORPES17)
Related Report
Int'l Joint Research
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[Presentation] Photo-induced transient electronic states of 2H-NbSe2 observed by time-resolved photemission spectroscopy2017
Author(s)
M. Watanabe, T. Suzuki, Y. Ogawa, T. Someya, S. Michimae, M. Fujisawa, T. Kanai, N. Ishii, J. Itatani, T. Saitoh, K. Okazaki, and S. Shin
Organizer
International Workshop on Strong Correlations and Angle-Resolved Photoemission Spectroscopy 2017 (CORPES17)
Related Report
Int'l Joint Research
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[Presentation] Polarization-emmission angle dependent hard x-ray photoemission study of thermoelectric Cu-based delafossite oxides2017
Author(s)
K. Takahashi, M. Okawa, A. Yasui, E. Ikenaga, T. Okuda, S. Ogata, M. Ota, N. Hamada, and T. Saitoh
Organizer
International Symposium on Novel Energy Nanomaterials, Catalysts, and Surfaces for Future Earth
Related Report
Int'l Joint Research
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