Multiple Reflection Effect on Spin-Transfer Torque Dynamics in Spin Valves with a Single or Dual Polarizer
Multiple Reflection Effect on Spin-Transfer Torque Dynamics in Spin Valves with a Single or Dual Polarizer
复制标题
具有单或双偏振器的自旋阀中自旋传递扭矩动力学的多重反射效应
DOI：
10.1142/s2010324715500034
复制
发表时间：
2015
期刊：
影响因子：
1.8
通讯作者：
Yaowen Liu
中科院分区：
文献类型：
--
作者：
Weiwei Zhu;Zongzhi Zhang;Jianwei Zhang;Yaowen Liu
本文从理论和数值计算两方面研究了自旋阀纳米柱中自旋相关的多次反射对自旋转移矩的影响。利用散射矩阵方法，推导出了包含界面多重反射效应的STT的解析表达式。结果表明，多重反射可以提高STT效率，降低临界开关电流。STT效率取决于自由层和偏振器两者的自旋偏振。在具有双自旋极化器的纳米柱中，多次反射将导致对所施加电流的非对称频率依赖性，尽管在所有三个铁磁层中使用完全相同的参数，这表明负电流中的频率变化比正电流中的频率变化快得多。
In this paper, spin-dependent multiple reflection effect on spin-transfer torque (STT) has been theoretically and numerically studied in a spin valve nanopillar with a single or dual spin-polarizer. By using a scattering matrix method, we formulate an analytical expression of STT that contains the multiple interfacial reflection effect. It is found that the multiple reflections could enhance the STT efficiency and reduce the critical switching current. The STT efficiency depends on the spin polarization of both the free layer and polarizer. In the nanopillars with a dual spin polarizer, the multiple reflections would cause an asymmetric frequency dependence on the applied current, albeit exactly the same parameters are used in all three ferromagnetic layers, indicating that the frequency in the negative current varies much faster than that in the positive case.