2015 Fiscal Year Final Research Report

Search for superconducting phase in electronic ferroelectric iron oxides

Research Project

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Project/Area Number	25620071
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Functional solid state chemistry
Research Institution	Japan Atomic Energy Agency
Principal Investigator	Yoshii Kenji 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門量子ビーム応用研究センター, 研究主幹 (90354985)
Co-Investigator(Kenkyū-buntansha)	KOBAYASHI Tatsuo 岡山大学, 自然科学研究科, 教授 (80205468) YONEDA Yasuhiro 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門量子ビーム応用研究センター, 研究主幹 (30343924) SAITOH Hiroyuki 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門量子ビーム応用研究センター, 研究主幹 (20373243) FUKUDA Tatsuo 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門量子ビーム応用研究センター, 研究副主幹 (80354984) MATSUMURA Daiju 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門量子ビーム応用研究センター, 研究副主幹 (30425566)
Co-Investigator(Renkei-kenkyūsha)	IKEDA Naoshi 岡山大学, 自然科学研究科, 教授 (00222894)
Project Period (FY)	2013-04-01 – 2016-03-31
Keywords	マルチフェロイック / 電子強誘電体 / 量子揺らぎ / 超伝導
Outline of Final Research Achievements	We have searched for a superconducting phase in electronic ferroelectric multiferroic RFe2O4 (R: rare earths). Electrical resistivity measurements were performed under high pressures up to 4 GPa to increase the interactions between the Fe ions inside the Fe-O plane. Although the pressure was raised up to 4 GPa, the system remained semiconducting. However, a slight change was observed for YFe2O4 around 1-2 GPa; the activation energy was slightly decreased at higher pressures. Also, the elemental substitution at R site was attempted. We found that the magnetic transition temperature (250 K) was increased by 5-10 K by the substitution of the large R3+ ion (Dy3+). This result is interesting from the viewpoint of a search for room temperature multiferroic materials.
Free Research Field	固体化学