在Ta/铁磁二层中没有轨道电流扭矩
Qianbiao Liu1, Lijun Zhu2,3
1State Key Laboratory of Semiconductor Physics and Chip Technologies, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
Nature communications
|October 1, 2025
概括
在Ta/铁磁磁系统中,轨道霍尔效应不会产生旋转轨道扭矩. 相反,Ta的旋转霍尔效应是界面扭矩的唯一来源,无论铁磁铁的类型或厚度如何.
科学领域:
- 这就是Spintronics.
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
背景情况:
- 理论上,轨道霍尔效应 (OHE) 在相邻的磁层中诱导非局部轨道电流和旋转轨道扭矩 (SOT).
- 调查OHE对SOT的贡献对于理解自旋电子设备机制至关重要.
研究的目的:
- 为了确定 (Ta) 中的OHE是否会在相邻的铁磁体 (FMs) 中产生非局部轨道电流和SOT.
- 为了澄清在Ta/FM异构结构中负责界面扭矩的主导机制.
主要方法:
- 利用旋转扭矩铁磁共振 (ST-FMR) 来分析各种Ta/FM (Ni,NiFe,Fe,FeCoB,FePt) 系统中的SOT效率.
- 研究了FM层厚度对ST-FMR信号和扭矩产生的影响.
主要成果:
- 在所有测试的Ta/FM系统中观察到持续负的SOT效率,不论FM材料如何.
- 确定了Ta的旋转霍尔效应 (SHE),而不是OHE,是界面扭矩的主要贡献者.
- 发现一些研究中以前报告的正扭矩估计是人工制造物,原因是忽视了FM层中厚度依赖的自诱导ST-FMR信号.
结论:
- 在Ta/FM系统中,OHE不会诱导显著的界面扭矩.
- 在这些异构结构中,Ta的SHE是SOT的主要来源.
- 准确地描述SOT需要仔细考虑FM层内的自我诱导信号.
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