Domain wall dynamics due to femtosecond laser-induced superdiffusive spin transport
Domain wall dynamics due to femtosecond laser-induced superdiffusive spin transport
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DOI：
10.1103/physrevb.101.174418
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发表时间：
2020-05-14
影响因子：
3.7
通讯作者：
Oppeneer, Peter M.
中科院分区：
文献类型：
--
作者：
Balaz, Pavel;Carva, Karel;Oppeneer, Peter M.
最近，通过一个螺旋度无关的激光脉冲的磁畴壁的操纵已被实验证明和各种物理机制，导致畴壁动力学进行了讨论。自旋相关的超扩散输运的热电子已被确定为一种可能的方式来影响磁畴壁。在这里，我们发展了一个基于超扩散自旋相关输运的模型来研究激光诱导超热电子通过光滑磁畴壁的输运。我们发现相邻畴间的自旋转移可以增强畴壁的超快退磁。更重要的是，我们的计算表明，当激光脉冲适当地聚焦到畴壁附近时，它可以激发足够强的自旋电流，产生自旋转移力矩，可以在几百飞秒内快速移动磁畴壁几纳米，导致巨大的非平衡畴壁速度。
Manipulation of magnetic domain walls via a helicity-independent laser pulse has recently been experimentally demonstrated and various physical mechanisms leading to domain wall dynamics have been discussed. Spin-dependent superdiffusive transport of hot electrons has been identified as one of the possible ways to affect a magnetic domain wall. Here, we develop a model based on superdiffusive spin-dependent transport to study the laser-induced transport of hot electrons through a smooth magnetic domain wall. We show that the spin transfer between neighboring domains can enhance ultrafast demagnetization in the domain wall. More importantly, our calculations reveal that when the laser pulse is properly focused onto the vicinity of the domain wall, it can excite sufficiently strong spin currents to generate a spin-transfer torque that can rapidly move the magnetic domain wall by several nanometers in several hundred femtoseconds, leading to a huge nonequilibrium domain wall velocity.