Relationship between magnetic anisotropy and anisotropic electronic structure studied by soft x-ray spectroscopy

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14416
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Japan Atomic Energy Agency (2022); Tokyo University of Science (2020-2021)
• Principal Investigator: Shibata Goro 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 原子力科学研究所 物質科学研究センター, 研究職 (20747026)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 磁気異方性 / 強磁性体 / X線磁気円二色性 / 薄膜 / 遷移金属化合物 / 軌道磁気モーメント / 電子軌道

Outline of Final Research Achievements

In this study, by using synchrotron spectroscopy techniques such as X-ray magnetic circular dichroism (XMCD) and X-ray magnetic linear dichroism (XMLD), we revealed the electronic states of ferromagnetic thin films and layered magnetic materials which can be applied for spintronics, and discussed the origin of the magnetic anisotropy of them. From the XMCD results of magnetic materials which shows perpendicular magnetic anisotropy, we pointed out that the perpendicular magnetic anisotropy can be seen in two dimensional systems with unquenched orbital magnetic moments both experimentally and theoretically. Moreover, by using a vector-magnet apparatus with which we can vary the direction of magnetic field freely, we performed XMLD experiments of layered ferromagnetic thin films, and succeeded in the direct observation of the change of the ‘shape’ of electron orbitals upon magnetic transitions.

Free Research Field

物性物理学、磁性、放射光分光

Academic Significance and Societal Importance of the Research Achievements

本研究成果は、磁気異方性を決定する要因である、磁性材料中の電子軌道の形状を推定する新しい手法を提供するものであり、手法開発の意味で学術的重要性があると考えられる。また、磁気異方性の強い材料はハードディスク等の記録媒体や高い保磁力を持つ永久磁石としても実社会で用いられており、これらの材料における磁気異方性の制御に関する指針を得ることは応用上の意義もあると考えられる。