2024 Fiscal Year Final Research Report
Study in the successive transition of the charge-ordering phase in electron ferroelectrics
| Project/Area Number |
23K23210
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| Project/Area Number (Other) |
22H01942 (2022-2023)
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Multi-year Fund (2024)
Single-year Grants (2022-2023) |
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| Section | 一般 |
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| Review Section |
Basic Section 29010:Applied physical properties-related
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| Research Institution | Okayama University |
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Principal Investigator |
IKEDA Naoshi 岡山大学, 環境生命自然科学学域, 教授 (00222894)
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| Co-Investigator(Kenkyū-buntansha) |
藤井 達生 岡山大学, 環境生命自然科学学域, 教授 (10222259)
沖本 洋一 東京科学大学, 理学院, 准教授 (50356705)
藤原 孝将 国立研究開発法人量子科学技術研究開発機構, 関西光量子科学研究所 放射光科学研究センター, 主任研究員 (50847150)
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| Project Period (FY) |
2024-04-01 – 2025-03-31
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| Keywords | 電子強誘電体 / lectron ferroelectrics, / RFe2O4 / LuFe2O4 / YbFe2O4 / YFe2O4 |
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| Outline of Final Research Achievements |
This research explores "electron ferroelectrics," exhibiting electric polarization from electron redistribution without ion displacement, promising ultra-low-energy and high-speed applications．The study aims to understand their origin and functions in rare-earth double-charge iron oxides (RFe2O4), particularly verifying that competing d-electron interactions drive electron stripe structures. Experiments on high-quality YFe2O4 crystals and films revealed precise control of polarization domains using short pulses, leading to a low-energy memory function superior to existing MRAM. Other findings include observing polarization hysteresis, a giant magnetostrictive effect in non-magnetic regions linked to spin fluctuations, and analyzing charge order melting by laser irradiation on distinct electronic and phononic timescales. An unknown phase transition near 300K was also identified. These results deepen the understanding of electron ferroelectricity and its potential applications.
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| Free Research Field |
固体物性
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| Academic Significance and Societal Importance of the Research Achievements |
本研究により、電子強誘電体のが示す優れた特性の基礎理解が進んだ。本研究の成果は、強相関電子系理解に立脚した新しい強誘電体の実在が明瞭になっただけではなく、本研究で見出した新現象から、近未来の文明発展の基礎を得た。例えば、極めて低エネルギーで動作する強誘電体デバイス、psecレベルで超高速応答する強誘電体デバイス、現在のMRAMなどに比べ10桁以上低いエネルギーでのメモリーデバイス、新しいTHz発生源、新原理で動作する巨大磁歪材料などである。
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