2021 Fiscal Year Final Research Report

Studies on nitride-based spintronics materials with perpendicular magnetic anisotropy

Research Project

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Project/Area Number	19K21954
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 21:Electrical and electronic engineering and related fields
Research Institution	University of Tsukuba
Principal Investigator	Suemasu Takashi 筑波大学, 数理物質系, 教授 (40282339)
Co-Investigator(Kenkyū-buntansha)	磯上慎二国立研究開発法人物質・材料研究機構, 磁性・スピントロニクス材料研究拠点, 主任研究員 (10586853)
Project Period (FY)	2019-06-28 – 2022-03-31
Keywords	スピントロ二クス / フェリ磁性体 / 磁化補償 / 角運動量補償 / 磁壁移動 / スピン移行トルク
Outline of Final Research Achievements	In spintronics, it is important to control the direction of the magnetization of the magnetic films to the zeros and ones of the information and to control them with electric current. The principal investigator and co-investigators have demonstrated ultra-fast domain wall motion in rare-earth free ferrimagnet Mn4N reaching 900m/s driven by pure spin transfer torques. They also demonstrated the magnetic compensation for Mn4N films doped with a small amount of Ni by x-ray magnetic circular dichroism measurement, and achieved at such a Ni composition ultra-fast domain wall motion as fast as 3000 m/s at room temperature without any assistance of external magnetic field. Such magnetic compensations were also demonstrated in Co-, Sn-, or Au-doped Mn4N films by x-ray magnetic circular dichroism measurement.
Free Research Field	電子工学、結晶成長工学
Academic Significance and Societal Importance of the Research Achievements	これまで、フェリ磁性体を用いて補償組成付近で超高速の磁壁移動を達成報告した例はあるが、Tb等の希少元素を含む材料であり、また、磁壁移動に外部磁場のアシストが必要であった。本研究で室温で超高速の磁壁移動を達成した材料は、希少元素を含まず、また、室温で外部磁場のアシストが不要な点に学術的な意義がある。