Investigation of hexagonal ferromagnet based systems toward voltage-controlled spintronics

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04482
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Nozaki Tomohiro 国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 研究員 (10610644)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 六方晶 / 電界制御 / 垂直磁気異方性 / 薄膜 / 界面

Outline of Final Research Achievements

In recent years, the voltage controlled magnetic anisotropy effect (VCMA effect) has been attracting attention as a ultra-low power consumption spin manipulation technique. In this study, we worked on a systematic investigation of the VCMA effect of systems with hexagonal Co-based ferromagnets, through a development of suitable tunnel barrier layers. By investigating VCMA effect using an amorphous tunnel barrier layers, we clarified the effect of interfacial oxidation, Co film thickness, post-annealing, and heavy metal element insertion on VCMA effect. We demonstrated the high potential of VCMA effect in Co-based systems, by showing a large voltage induced coercivity change. In addition, we worked on the development of a hexagonal crystal tunnel barrier.

Free Research Field

スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

スピントロニクス分野の材料開発は、立方晶系Fe/MgOトンネル接合が圧倒的な高い性能を示すことと、六方晶系強磁性材料に適したトンネル障壁層がないことから、そのほとんどが立方晶系の材料に限られてきた。その中で本研究では、電圧制御という切り口で、六方晶Co系スピントロニクス材料の有用性を示すための研究を行い、その第一歩となる高効率電圧スピン制御を示す成果を上げることができた。本成果は単に電圧制御型MRAMの実用化に向けて重要なだけでなく、スピントロニクス分野の材料選択や研究の幅を広げる点で大きな意義がある。