Theoretical Study on Transformation between Electric Power and Motive Power Mediated by Spin for Electricity Self-Generation Type Nanomachine

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K04930
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied materials
• Research Institution: Shizuoka University
• Principal Investigator: Kokado Satoshi 静岡大学, 工学部, 教授 (50377719)
• Co-Investigator(Kenkyū-buntansha): 角田 匡清 東北大学, 工学研究科, 准教授 (80250702)
• Project Period (FY): 2016-10-21 – 2020-03-31
• Keywords: 伝導電子－スピン相互作用 / スピン－分子運動相互作用 / スピン軌道相互作用 / 結晶場 / s-d散乱 / 異方性磁気抵抗効果 / 摂動論

Outline of Final Research Achievements

"Electric generation type nanomachine", in which motions can be properly remote-controlled and travel motions are performed by the self-generated electric power, needs the mutual transformation between electron conduction and molecular motions. We proposed an idea that interactions between electrons and molecular motions mediated by localized spins can be used in the transformation. To formulate this V, we must find properties of s-d scatterings from the conduction (s) electron to the localized d orbitals. In this study, we theoretically studied the s-d scattering and anisotropic magnetoresistance (AMR) effect, which directly reflects the s-d scattering. We first developed the s-d scattering theory for a model with the crystal field, and then qualitatively explained experimental results of the AMR effects for Ni, Fe, and half-metal, which had not been explained by conventional theories.

Free Research Field

物性理論

Academic Significance and Societal Importance of the Research Achievements

我々は自己発電型ナノマシンの開発に必要な伝導電子からd軌道への電子散乱に注目し，その散乱を直接反映する異方性磁気抵抗(AMR)の理論を開発した．AMRは電気抵抗が磁化方向に依存する現象であり，約160年前から実験を中心に研究されてきた．一方，一部の散乱のみを取り入れた従来理論は特定の物質には有効なものの汎用性は低かった．本研究では全ての散乱を取り入れ，ハーフメタルを含む種々の物質に適用可能な理論を開発した．本理論により，従来理論では説明できなかったNi, Fe, ハーフメタルのAMRの説明に成功し，また磁性材料にとって重要なd軌道状態をAMRで容易に調べられ得ることも確認された．