2022 Fiscal Year Final Research Report

Electrical detection of magnetic fluctuations with spin current and development of high efficiency spin conversion in two-dimensional magnetic materials

Research Project

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Project/Area Number	20H02557
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 28020:Nanostructural physics-related
Research Institution	Osaka University
Principal Investigator	Niimi Yasuhiro 大阪大学, 大学院理学研究科, 教授 (00574617)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	スピン流 / 原子層磁性体 / 二次元 / スピン変換
Outline of Final Research Achievements	In this research project, we have aimed to expand the material group of van der Waals (vdW) magnets, which have been rapidly progressing in recent years, and also to electrically detect magnetic fluctuations in the vdW magnets near the magnetic transition temperature through spin conversion. In the atomic-layer antiferromagnet CeTe3, quantum oscillation with magnetic properties was observed below the magnetic transition temperature. In the triangular-lattice antiferromagnet Ag2CrO2, a unique anomalous Hall effect was observed below the magnetic transition temperature. We also measured the spin torque in atomic-layer ferromagnet Fe5GeTe2 and ferromagnetic permalloy bilayer films, and observed a large signal change below the magnetic transition temperature. These results demonstrate that magnetic transitions have a strong influence on spin conversion.
Free Research Field	スピントロニクス
Academic Significance and Societal Importance of the Research Achievements	スピン流電流変換を用いたスピントロニクスデバイスへの応用という観点では、単純な金属だけでは限界があり、トポロジカル絶縁体、ワイル半金属、超伝導体などを用いた研究が近年進展している。そのような背景の中で、本研究課題で用いた原子層磁性体は新しい研究の方向性となり得る。最近、原子層磁性体の磁気転移温度が室温を超える物質も数多く開拓され、原子層磁性体を用いたデバイス応用への機運が高まっている。特に本研究で用いたFe5GeTe2は強磁性転移温度が室温付近にあり、転移温度から少し温度を下げるだけで、スピン変換効率が劇的に大きくなるため、原子層強磁性体を用いた高効率な磁気デバイスへの応用が期待できる。