2021年度 提案書 （Web公開用）

作成者：Nguyen Thi Van Anh （東北大CSIS）

研究プロジェクト名： Investigation of efficient charge-spin conversion
in the non-magnetic/ferromagnetic stack films
概要： This study focuses on the investigation of efficient charge-spin conversion in the nonmagnetic/ferromagnetic (NM/FM) stack films with various NM materials such as the oxides. In
particular, the relationship between the efficiency for conversion and the static and dynamic
magnetic properties such as the magnetic anisotropy and the damping constant will be investigatedunder the control of the interfacial conditions. The achievements here would contribute to therealization of new concepts of spintronic devices.

コアメンバー： Nguyen Thi Van Anh（東北大） 、遠藤(恭）（東北大）、遠藤（哲）グループ（東北大) 、深見グループ（東北大）
期待される研究成果：
The investigation of efficiency forcharge-spin conversion in NM/FM stackfilms and its relationship with the staticand dynamic magnetic properties
would be beneficial for both device
applications, and the designing ofguidelines for researches on nextgenerationenergy-saving spintronicdevices.

2020年度 報告書 （Web公開用）

作成者： Nguyen Thi Van Anh （東北大CSIS）

研究プロジェクト名： Investigation of efficient charge-spin conversion
in the non-magnetic/ferromagnetic stack films
概要： Spin-orbit torque induced magnetization switching in oxide/ferromagnetic stacks has attracted
immense interest owing to its potential for the development of high-performance spintronic devices,
realized by tuning the surface oxidization. Since both of the Slonczewski-like (HSL) and the field-like (HFL)
effective fields would contribute to the magnetization reversal, a detailed understanding andmanipulation of HSL and HFL in these structures are necessitated. This request has been shown in this study
for a typical Ta-O/Co-Fe-B stacks, which would be beneficial for spintronic device applications.

研究成果（実施状況）： Using the Harmonic
Hall measurement, HSL and HFL for Ta-O/Co-FeB stacks with different Ta-O thickness (tTa-O)
were evaluated. Fig. 1 shows that both of|HSL/I| and |HFL/I| increase and converge to acertain value as tTa-O increases. Moreover,|HFL/I| is higher than |HSL/I|. These results
suggest the contributions of both of the bulk
and interfacial effects to the magnetization
reversal process of this system. This researchwould be important for designing spintronic
devices, and opening the guidelines for next
researches on oxide-based spintronics.

主要発表論文等： [1] T. V. A. Nguyen et al., Abstract for 81th JSAP Autumn Meeting,2020; [2] Abstract for 68th JSAP Spring Meeting (2021) .他

2021年度 報告書 （Web公開用）

作成者： Nguyen Thi Van Anh （東北大CSIS）

研究プロジェクト名： Investigation of efficient charge‐spin conversion
in the non‐magnetic/ferromagnetic stack films
概要： To understand the charge‐spin conversion in Ta(O)/Co‐Fe‐B bilayer films with the different
levels of the oxygen incorporation into the Ta(O) layer, we studied the corresponding changes in the
dynamic magnetic properties under both in‐plane and out‐of‐plane magnetic fields using
ferromagnetic resonance measurement technique. The spin‐orbit torque (SOT) induced
magnetization switching in Ta(O)/Co‐Fe‐B bilayer films was investigated by using extended harmonic
Hall measurement.
研究成果（実施状況）： Dynamic magnetic
properties of Ta(O)/Co‐Fe‐B bilayer films arestrongly influenced by the oxidation conditionof the Ta(O) layer. In Fig. 1 (a), a slight changeof the oxygen incorporation into the Ta‐O layer
would decreases the in‐plane and out‐of‐plane
damping constants (IP and OP). Fig. 1 (b)shows the current density dependence of theSOT effective fields (HSL, HFL) in different
bilayers with different oxidation condition andvarious thicknesses of the Ta(O) layer. Theseresults suggest that it is possible to control theSOT effective fields by tuning the oxygen
incorporation into the Ta(O) layer.

主要発表論文等： [1] T.V.A. Nguyen et al., AIP Advances, 12, 035133 (2022).
[2] T.V.A. Nguyen et al., IEEE International Magnetics Conference, 2021.