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2021 年度 実施状況報告書

量子井戸効果を用いたスピン軌道トルクの制御:電流―スピン流変換の新しい自由度

研究課題

研究課題/領域番号 21K14523
研究機関東北大学

研究代表者

杜 野  東北大学, 先端スピントロニクス研究開発センター, 学術研究員 (70795319)

研究期間 (年度) 2021-04-01 – 2024-03-31
キーワードSpin-orbit torque / Quantum confinement / Spin current
研究実績の概要

The current-induced spin-orbit torque (SOT) has been shown to be an efficient means to control the local magnetization electrically. On one hand, efficient spin-current generation using high-conductivity materials is desirable to achieve small energy loss; on the other hand, the ability to control the sign of the effective spin Hall angle may stimulate new spintronic functions. Here in this proposal, we aim to realize effective control (magnitude and sign) of spin-current generation in high-conductivity magnetic hetero-structures via a coherent control of electron spin (e.g. the quantum-confinement effect). Firstly, we have successfully prepared epitaxial Cu/Co bilayers upon a MgO substrate. Thin films show desirable interlayer flatness. Secondly, we have fabricated magnetic devices by using such bilayers and studied the current-induced SOT. The SOT measurement procedure has been optimized. As a result, we have found that both the magnitude and sign of the SOT oscillate with varying Cu thickness. This suggests that it is possible to manipulate the spin-current generation by taking advantage of the Cu band structure (Fermi surface). Our study potentially adds a new degree of freedom to the control of charge-spin current generation in high-conductivity magnetic hetero-structures.

現在までの達成度 (区分)
現在までの達成度 (区分)

2: おおむね順調に進展している

理由

We successfully prepared epitaxial Cu/Co bilayers and studied the current-induced spin-orbit torque (SOT) in such magnetic hetero-structures. As a result, we found both the magnitude and sign of SOT oscillate as a function of Cu thickness. The results are consistent with our expectation. Therefore, our project is progressing smoothly.

今後の研究の推進方策

On one hand, we aim to gain a better physical understanding of the current experimental results. This can be achieved by collaborating with theoretical researchers working on the current-induced spin-orbit torque (SOT). The mechanism of the SOT oscillation via the quantum confinement effect will be explored. On the other hand, we aim to prepare higher-quality magnetic hetero-structures by using the molecular-beam epitaxy technique (the present material preparation method is magnetron sputtering). With this technique, electron quantum confinement channel is expected to have longer mean free path and more pronounced effect on the SOT manipulation will be anticipated.

次年度使用額が生じた理由

物品の納期が延期され、年度内の支払いはできなくなり、残額は次年度の物品費(基板など)として使用します。

  • 研究成果

    (1件)

すべて 2022

すべて 学会発表 (1件)

  • [学会発表] Possibility of controlling spin-orbit torque with quantum confinement effect2022

    • 著者名/発表者名
      Ye Du, Shutaro Karube, Makoto Kohda, and Junsaku Nitta
    • 学会等名
      第69回応用物理学会春季学術講演会

URL: 

公開日: 2022-12-28  

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