Laser-induced deterministic magnetization switching for next-generation magnetic recording

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K14521
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 29010:Applied physical properties-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: WANG Jian 国立研究開発法人産業技術総合研究所, 材料・化学領域, 研究員 (80792069)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: エネルギーアシスト磁化反転 / FePt媒体 / 光誘起磁化反転 / 熱流スピン流変換 / 超高密度磁気記録

Outline of Final Research Achievements

Nowadays, the question of how, and how fast, magnetization can be reversed is attracting great practical interest in hard disk drive (HDD) community. In this project, we successfully demonstrate a clearly enhanced all optical magnetic switching (AOS) in magnetic hard L10-ordered FePt continuous/nanogranular films deposited on yttrium iron garnet (YIG) single crystal substrate. The enhancement was confirmed by comparing with similar FePt thin films deposited on gadolinium gallium garnet single crystal substrate. The enhancement was considered due to a thermal-induced spin-transfer torque via the spin Seebeck effect in YIG substrate with a tremendous temperature gradient induced by the laser exposure. For practical application, the quantification of the enhancement and optimization of the thin film (especially the nanogranular film) microstructure will be necessary to achieve a laser-induced deterministic magnetization switching in magnetically hard FePt nanogranular film.

Free Research Field

応用物性（磁性材料）

Academic Significance and Societal Importance of the Research Achievements

この研究成果の基礎となる新しい物理現象は、熱（フォノニック）、光（フォトニック）、スピン磁気モーメント（スピントロニクス）、ナノ磁性の相互変換に関する新たな学術研究分野を促進するとともに、次世代磁気記録媒体（特にHDD）の研究開発に新たな知見を提供するものである。