2019 Fiscal Year Final Research Report
Scientific principle elucidation of bulk spin orbit torque and its application for spin devices
| Project/Area Number |
17H03240
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | Toyota Technological Institute |
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Principal Investigator |
AWANO HIROYUKI 豊田工業大学, 工学(系)研究科(研究院), 教授 (40571675)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | バルクスピン軌道トルク / 磁性細線メモリ / スピンロジック / 磁壁駆動速度 / 希土類・遷移金属合金 / フェリ磁性材料 / 電流磁壁駆動 / 臨界電流密度 |
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| Outline of Final Research Achievements |
Current driven domain wall motions of Rare Earth (RE) - Transition Metal (TM) / Pt magnetic wire were observed. In the case of TbCo/Pt magnetic wire, the domain wall (DW) moves along to the current direction by spin orbital torque (SOT) due to the hetero-interface. The DW velocity was 100 m/sec. The Tb has large orbital magnetic moment (L). Therefore, the ferri-magnetic coupling between Tb and Co was dispersed, the SOT was also dispersed. If it is the cause of the slow domain wall speed, making a GdFeCo/Pt magnetic wire using a small L Gd may increase the domain wall speed by the current. As a result of experiment, we succeeded in increasing the domain wall speed of GdFeCo to 2600 m/sec. Next, the thickness of the GdFeCo layer on which the SOT effectively works was investigated. Surprisingly, even if the GdFeCo thickness is 500 nm, the domain wall moves still in the current direction by SOT. Thus,by using RE-TM magnetic layer, the SOT interface effect can be improved to bulk effect.
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| Free Research Field |
スピントロニクス
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| Academic Significance and Societal Importance of the Research Achievements |
磁性膜と重金属膜のヘテロ界面にはジャロシンスキー守谷相互作用とスピンホール効果が発現し、スピントロニクスデバイスの新たな駆動原理として期待されている。しかし、これは界面効果であるため界面数nmにしか及ばず応用上の問題であった。そこで、希土類金属と遷移金属からなるRE-TM磁性膜と重金属膜を積層した磁性細線を作成し、電流磁壁駆動の実験を行ったところ、驚いたことにこの界面効果がTbCoでは15nm程度、GdFeCoでは500nm以上にまで及ぶことがわかった。このバルク的に利用可能なバルクスピン軌道トルクは高機能省電力メモリやロジック等の新たなスピンエレクトロニクス技術への応用展開が期待できる。
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