Gilbert damping in magnetic multilayers
Gilbert damping in magnetic multilayers
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DOI：
10.1103/physrevb.67.144418
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发表时间：
2002-07
影响因子：
3.7
通讯作者：
E. Simanek;B. Heinrich
中科院分区：
文献类型：
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作者：
E. Simanek;B. Heinrich
我们研究了由于相邻的正常金属层的薄膜铁磁弛豫速率的增强。利用线性响应理论，我们推导出耗散扭矩所产生的交换相互作用在铁磁体正常金属界面。对于一个缓慢的进动，吉尔伯特阻尼常数的增强是成比例的平方的交换常数乘以零频率限制的本地动态自旋磁化率的频率导数的正常金属在界面上。电子-电子相互作用使弛豫速率增加斯通纳因子的平方。我们属性的大各向异性增强最近在多层膜中观察到的弛豫速率含钯这种机制。对于自由电子，本理论与Tserkovnyak等人[Phys. Rev. Lett. 88美元，117601美元（2002年）]。
We study the enhancement of the ferromagnetic relaxation rate in thin films due to the adjacent normal-metal layers. Using linear-response theory, we derive the dissipative torque produced by the $s\ensuremath{-}d$ exchange interaction at the ferromagnet--normal-metal interface. For a slow precession, the enhancement of the Gilbert damping constant is proportional to the square of the $s\ensuremath{-}d$ exchange constant times the zero-frequency limit of the frequency derivative of the local dynamic spin susceptibility of the normal metal at the interface. Electron-electron interactions increase the relaxation rate by the Stoner factor squared. We attribute the large anisotropic enhancements of the relaxation rate observed recently in multilayers containing palladium to this mechanism. For free electrons, the present theory compares favorably with recent spin-pumping results of Tserkovnyak et al. [Phys. Rev. Lett. $88,$ 117601 (2002)].