Dynamics of induced moment at the interface between platinum and ferromagnetic materials

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05028
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied materials
• Research Institution: Tohoku University
• Principal Investigator: Nobuaki Kikuchi 東北大学, 多元物質科学研究所, 助教 (80436170)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 強磁性共鳴 / X線磁気円二色性 / スピントロニクス

Outline of Final Research Achievements

Magnetization behaviors of a Co/Pt layer and CoCrPt-SiO2 granular media were investigated by X-ray magnetic circular dichroism (XMCD) with focused hard X-ray in 100 nm scale. The samples were excited by spin-polarized current or magnetic field in GHz frequency range. XMCD measurement have revealed that the polarized Pt moment were strongly coupled with Co moment, indicating that XMCD signal of Pt can be used as a probe for magnetization dynamics measurement of those multilayer and alloys. Two-dimensional mapping measurement have revealed that the cluster size during microwave assisted switching in CoCrPt-SiO2 granular media strongly depends on the excitation frequency, and the size becomes smaller with increasing of frequency.

Free Research Field

磁化ダイナミクス

Academic Significance and Societal Importance of the Research Achievements

Ptを含む積層膜や合金は，大きな磁気異方性を発現し，また，それらに含まれるPt自身も大きな磁気モーメントを持つことが知られている．このPtの磁気モーメントの磁化ダイナミクスの解明が新たなデバイスの創成に重要であるが，既存の手法での計測は困難であった．そこで，本課題では元素選択性を実現できる放射光を用いることで，Pt原子のモーメントのGHz帯域での挙動を明らかにすることを目指した．