Precise study on the optical and dielectric response of the stoichiometric iron based electronic ferroelectrics

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H01827
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: Okayama University
• Principal Investigator: IKEDA NAOSHI 岡山大学, 自然科学学域, 教授 (00222894)
• Co-Investigator(Kenkyū-buntansha): 沖本 洋一 東京工業大学, 理学院, 准教授 (50356705)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 電子強誘電体 / RFe2O4 / LuFe2O4 / YbFe2O4 / YFe2O4

Outline of Final Research Achievements

This research has demonstrated for the first time in the world that an electron ferroelectric material exists stably at room temperature. Furthermore, we were able to show that this electronic phase also exists in thin film samples. The electric polarization consisting of only the electron distribution in the electron ferroelectric material is expected to respond significantly faster than that in the displacement-type ferroelectric material, which has been known until now.
A new dielectric relaxation analysis method using single crystals was developed for the electric polarization of electronic ferroelectrics, which inevitably involves the electric resistivity. As a result, we were able to experimentally show for the first time that in fine charge-ordered domains, charge-ordered nanoregions with larger capacitance have higher electrical resistance.

Free Research Field

誘電体

Academic Significance and Societal Importance of the Research Achievements

電子型強誘電体は、電子応答だけが誘電応答を示すため、既存の強誘電体に比べ、3桁程度早く、また低エネルギーで応答することが可能であると期待されている。本研究によるその実在の確認は、現状に比べ情報密度や省エネルギー性が３桁向上した、将来の超高速情報通信社会形成のために、重要な基盤材料を提示できたと考えられる。
この材料が産業利用に整合するためには、多くの精査が必要であろうが、本研究はその第一歩となった。