Electronic state of half-metal-type Heusler alloy proved by resonant inelastic soft X-ray scattering in magnetic field

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01690
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 26010:Metallic material properties-related
• Research Institution: Tohoku University
• Principal Investigator: Umetsu Rie 東北大学, 金属材料研究所, 教授 (60422086)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: ハーフメタル型強磁性体 / スピントロニクス / 電子状態 / 共鳴非弾性X線散乱 / 異方性磁気抵抗

Outline of Final Research Achievements

Soft X-ray resonance inelastic X-ray scattering (RIXS) measurements were performed on candidate materials for the Heulser alloy, which is theoretically predicted to have a spin polarization of 100% around the Fermi level in the electronic state.
For Mn2VAl and Co2MnSi, clear magnetic circular dichroism (MCD) was observed in the RIXS spectrum of the 2p3/2 absorption peaks of Mn, V, and Co. It was found that the sign of MCD of Mn was different between them, and it reflected the difference in the electronic state of each other.
In Co2FeSi, a large MCD component was observed just beside the elastic scattering at the Fe-2p3/2 absorption peak, demonstrating that it reflects the large DOS of Fe existing at the Fermi level.

Free Research Field

金属物性

Academic Significance and Societal Importance of the Research Achievements

理論的には多くの物質がハーフメタル型電子状態を有することが予測され、スピントロニクスの分野で有用であると提案されているのに対し、その電子状態が納得のいく実験結果で検証されている例ははかった。本研究では、良質のバルク単結晶試料を育成し、軟X線共鳴非弾性X線散乱測定により、ハーフメタル型電子状態を世界で初めて実証した点で、学術的意義が非常に高い。本研究により、ハーフメタル型強磁性体の電子状態を調べるのに、放射光を用いた軟X線RIXS測定が非常に有効な手段であることが示された点は社会的意義も高い。