Relativistic theory of magnetic inertia in ultrafast spin dynamics
Relativistic theory of magnetic inertia in ultrafast spin dynamics
复制标题
超快自旋动力学中磁惯量的相对论理论
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
P. Oppeneer
中科院分区：
文献类型：
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作者：
Ritwik Mondal;M. Berritta;A. Nandy;P. Oppeneer
可能的磁惯性效应的影响最近引起了人们对超快磁化动力学和开关的关注。本文在Dirac-Kohn-Sham框架的基础上，严格地导出了Landau-Lifshitz-吉尔伯特方程的惯性描述.使用Foldy-Wouthuysen变换直到1/c^4$的数量级，通过2$^{
动力学运动方程中磁化强度的m阶时间导数。因此，惯性阻尼$mathcal{I}$是一种高阶自旋-轨道耦合效应，$sim 1/c^4$，而吉尔伯特阻尼$Gamma$的阶数为$1/c^2$。因此，预计惯性只在超短时间尺度（亚皮秒）上发挥作用。我们还表明，吉尔伯特阻尼和惯性阻尼是通过磁化率张量的虚部和真实的部相互关联的。
The influence of possible magnetic inertia effects has recently drawn attention in ultrafast magnetization dynamics and switching. Here we derive rigorously a description of inertia in the Landau-Lifshitz-Gilbert equation on the basis of the Dirac-Kohn-Sham framework. Using the Foldy-Wouthuysen transformation up to the order of $1/c^4$ gives the intrinsic inertia of a pure system through the 2$^{
m nd}$ order time-derivative of magnetization in the dynamical equation of motion. Thus, the inertial damping $mathcal{I}$ is a higher order spin-orbit coupling effect, $sim 1/c^4$, as compared to the Gilbert damping $Gamma$ that is of order $1/c^2$. Inertia is therefore expected to play a role only on ultrashort timescales (sub-picoseconds). We also show that the Gilbert damping and inertial damping are related to one another through the imaginary and real parts of the magnetic susceptibility tensor respectively.