Interplay of magnon and electron currents in magnetic heterostructure
Interplay of magnon and electron currents in magnetic heterostructure
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磁性异质结构中磁振子和电子流的相互作用
DOI：
10.1103/physrevb.96.024449
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发表时间：
2017
影响因子：
3.7
通讯作者：
Zhang, Shufeng
中科院分区：
文献类型：
--
作者：
Cheng, Yihong;Chen, Kai;Zhang, Shufeng
在磁性材料中，电子和磁振子都能够携带角动量电流。外电场可以有效地驱动电子的电荷和自旋电流，但它不能直接产生不带电的磁振子电流。磁振子电流的产生通常通过热梯度或来自界面的电子自旋注入来实现。本文研究了磁性层状体系中传导电子的动量和角动量转移引起的磁振子电流。利用电子与磁振子之间的一般交换相互作用，导出了电子自旋与磁振子的耦合扩散方程，并发现：（a）对于常规导电铁磁体，磁振子电流与电荷电流之比在室温下是相当大的;（B）电子的自旋扩散长度因磁振子密度的非平衡而显著改变，以及（c）与不考虑磁振子电流的现有理论相比，对于垂直于层平面的电流，磁性多层的巨磁阻减小。
In magnetic materials, both electrons and magnons are capable of carrying angular momentum currents. An external electric field can efficiently drive a charge and spin current of electrons, but it is unable to directly produce a chargeless magnon current. The generation of the magnon current is conventionally achieved via thermal gradients or the electron spin injection from interfaces. Here, we investigate the magnon current induced by the momentum and angular momentum transfer from conduction electrons in magnetic layered systems. By using the generic exchange interaction between electrons and magnons, we derive the coupled diffusion equations for electron spins and magnons and we find (a) the ratio between the magnon current and the electric charge current is substantial at room temperature for conventional conducting ferromagnets, (b) the spin diffusion length of electrons is significantly modified by the presence of the nonequilibrium magnon density, and (c) the giant magnetoresistance of the magnetic multilayers for the current perpendicular to the plane of layers is reduced compared to the prior theory without taking into account the magnon current.