2020年度 提案書 （Web公開用）

作成者： Jian WANG （東北大 CSRN）

研究プロジェクト名： Magneto-optical manipulation of magnetizationin ferrimagnetic multilayers
概要： The ultrafast control of magnetism without using magnetic fields enables the integration of spintronic
devices in a large scale for memory, computation, and communication in the beyond-CMOS era. Ultrafast
magneto-optical interaction provides a promising approach rather than conventional charge and spin current.
In this collaboration research, we will explore the all-optical magnetic switching in ferrimagnetic multilayers(e.g. [CoGd/Pt]n multilayer). By optimization of the multilayer parameters (e.g. composition, layer thickness,
and number of repeats, n) and laser condition, we hope to achieve a deterministic (100%) single-laser-pulse
magnetic switching in our ferrimagnetic multilayers. The sample fabrication and basic measurements will beconducted at IMR, while the magneto-optical evaluation will be carried out at NIMS.

コアメンバー： Jian Wang（東北大 CSRN） 、 高橋グループ（NIMS）
期待される研究成果：
The successful demonstration of single-laserpulse magnetic switching in our ferrimagnetic
multilayers will provide new perspective of theinterfacial effect on the magneto-opticalinteraction. Moreover, it may promote an uniquestep toward integrated optospintronic devices
that combines spintronics and photonics
technologies to enable ultrafast conversion
between fundamental information carriers ofelectron spins and photons. At the end of this FY
2020, one scientific paper and/or patent can beexpected through the collaboration research.

（図面）

Figure. Demonstration of all-optical magnetic switching in FeTb alloy thin film: (b) MOKE image and (d)AHE loop. The start mark stands for the Hall resistance change before and after laser illumination.

J. Wang et al., Nat. Commun. 11, 2 (2020)

2020年度 報告書 （Web公開用）

作成者： Jian WANG （東北大 CSRN）

研究プロジェクト名：Magneto-optical manipulation of magnetizationin ferrimagnetic multilayers
概要： The ultrafast control of magnetism without using magnetic fields enables the integration of spintronic
devices in a large scale for memory, computation, and communication in the beyond-CMOS era. In thiscollaboration research, we explored the all-optical magnetic switching in ferrimagnetic multilayers (e.g.
[CoGd/Pt]n multilayer). By optimization of the multilayer parameters (e.g. composition, layer thickness, andnumber of repeats, n) and laser condition, we achieved a deterministic (~90%) single-laser-pulse magnetic
switching in our ferrimagnetic multilayers. The sample fabrication and basic measurements were conducted
at IMR, while the magneto-optical evaluation were carried out at NIMS.
研 究 成 果 （ 実 施 状 況 ） ： The Co100-xGdx/Pt
multilayer studied in this project shows
perpendicular magnetic anisotropy (PMA) and alloptical helicity-independent switching, which
provides a promising route for ultrafastmagnetization manipulation. Our study clarified
that the PMA of multilayers mainly originates notfrom the bulk property of ferrimagnetic Co100-xGdx,
but from the interface magnetic anisotropy. In
addition, the interfacial induced magnetic moment
significantly modulates the magneto-opticalresponse. Our findings are beneficial not only forunderstanding the mechanism of AOS but also fordesigning the spintronic devices using ferrimagnets.

Figure. Layer thickness and composition dependence ofstatic magnetic properties (magnetic anisotropy & interfacial
magnetic moment) and all-optical helicity-independent
switching probability of Co100-xGdx (t) / Pt multilayers.

主要発表論文等： [1] “Origin of Magnetic Anisotropy, Role of Induced Magnetic Moment and All-OpticalMagnetization Switching for Co100-xGdx/Pt Multilayers” Jian Wang, Takeshi Seki*, Yong-Chang Lau, Y. K.
Takahashi, and Koki Takanashi (submitted).