Current induced torques and interfacial spin-orbit coupling: Semiclassical modeling
Current induced torques and interfacial spin-orbit coupling: Semiclassical modeling
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DOI：
10.1103/physrevb.87.174411
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发表时间：
2013-05-07
影响因子：
3.7
通讯作者：
Stiles, M. D.
中科院分区：
文献类型：
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作者：
Haney, Paul M.;Lee, Hyun-Woo;Stiles, M. D.
在由铁磁层和具有强自旋轨道耦合的非磁层组成的双层纳米线中，电流在磁化过程中产生的扭矩超过了简单的铁磁纳米线。由此产生的磁动力学似乎需要扭矩，这些力矩可以分为两个项，即类阻尼力和类场力矩。类阻尼力矩通常从描述体自旋霍尔效应和自旋转移扭矩的模型中得到，类场力矩通常从描述界面自旋轨道耦合的Rashba模型中得到。我们基于玻尔兹曼方程导出了一个统一这些方法的模型。我们还考虑了玻尔兹曼方程的近似，漂移-扩散模型，它定性地再现了这种行为，但在某些区域定量上不同。我们发现，物理上合理的参数的Boltzmann方程可以匹配任何特定样品的扭矩，但在某些情况下，它不能描述实验观察到的厚度依赖关系。
In bilayer nanowires consisting of a ferromagnetic layer and a nonmagnetic layer with strong spin-orbit coupling, currents create torques on the magnetization beyond those found in simple ferromagnetic nanowires. The resulting magnetic dynamics appear to require torques that can be separated into two terms, dampinglike and fieldlike. The dampinglike torque is typically derived from models describing the bulk spin Hall effect and the spin transfer torque, and the fieldlike torque is typically derived from a Rashba model describing interfacial spin-orbit coupling. We derive a model based on the Boltzmann equation that unifies these approaches. We also consider an approximation to the Boltzmann equation, the drift-diffusion model, that qualitatively reproduces the behavior, but quantitatively differs in some regimes. We show that the Boltzmann equation with physically reasonable parameters can match the torques for any particular sample, but in some cases, it fails to describe the experimentally observed thickness dependencies.