Unidirectional magnetoresistance and spin-orbit torque in NiMnSb
Unidirectional magnetoresistance and spin-orbit torque in NiMnSb
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NiMnSb 中的单向磁阻和自旋轨道扭矩
DOI：
10.1103/physrevb.104.054429
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发表时间：
2021
影响因子：
3.7
通讯作者：
C. Ciccarelli
中科院分区：
文献类型：
--
作者：
J. Železný;Z. Fang;K. Olejn'ik;J. Patchett;F. Gerhard;C. Gould;L. Molenkamp;C. Gómez;J. Zemen;T. Tich'y;T. Jungwirth;C. Ciccarelli
由于相对论性自旋轨道耦合和空间反演对称性破缺而导致的自旋相关输运现象通常很难在微观上解释，特别是当发生在表面或界面时。在这里，我们提出了一个理论和实验研究的自旋轨道扭矩和单向磁电阻在模型室温铁磁体NiMnSb与反转不对称的散装半赫斯勒晶体。除了磁化的角度依赖性，Rashba和Dresselhaus类自旋轨道耦合的竞争导致这些效应对所施加的电场的晶体方向的依赖性。我们观察到的现象学突出了通常认为的解释实验的方法的潜在不适用性。我们指出，在一般情况下，有没有直接的联系之间的电流诱导的非平衡自旋极化推断从测量的自旋轨道扭矩和单向磁阻。我们还强调，单向磁阻不仅具有纵向，而且在电场中的横向分量-电流指数，这使其分离的热电贡献的检测信号在常见的实验技术复杂。我们使用的理论结果来分析我们的测量的谐振和非谐振混频信号的微棒器件制造从外延NiMnSb薄膜沿着不同的晶体方向。基于分析，我们提取的单向磁阻在NiMnSb的实验估计。
Spin-dependent transport phenomena due to relativistic spin-orbit coupling and broken space-inversion symmetry are often difficult to interpret microscopically, in particular when occurring at surfaces or interfaces. Here we present a theoretical and experimental study of spin-orbit torque and unidirectional magnetoresistance in a model room-temperature ferromagnet NiMnSb with inversion asymmetry in the bulk of this half-heusler crystal. Besides the angular dependence on magnetization, the competition of Rashba and Dresselhaus-like spin-orbit couplings results in the dependence of these effects on the crystal direction of the applied electric field. The phenomenology that we observe highlights potential inapplicability of commonly considered approaches for interpreting experiments. We point out that, in general, there is no direct link between the current-induced non-equilibrium spin polarization inferred from the measured spin-orbit torque and the unidirectional magnetiresistance. We also emphasize that the unidirectional magnetoresistance has not only longitudinal but also transverse components in the electric field -- current indices which complicates its separation from the thermoelectric contributions to the detected signals in common experimental techniques. We use the theoretical results to analyze our measurements of the on-resonance and off-resonance mixing signals in microbar devices fabricated from an epitaxial NiMnSb film along different crystal directions. Based on the analysis we extract an experimental estimate of the unidirectional magnetoresistance in NiMnSb.
C1b型NiMnSb半霍斯勒合金薄膜低温反常能斯特效应异常
影响因子：
1.5
作者：
Sharma Himanshu;Wen Zhenchao;Takanashi Koki;Mizuguchi Masaki
通讯作者：
Mizuguchi Masaki