Dependence of the efficiency of spin Hall torque on the transparency of Pt/ferromagnetic layer interfaces
Dependence of the efficiency of spin Hall torque on the transparency of Pt/ferromagnetic layer interfaces
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DOI：
10.1103/physrevb.92.064426
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发表时间：
2015-08-31
影响因子：
3.7
通讯作者：
Buhrman, R. A.
中科院分区：
文献类型：
--
作者：
Pai, Chi-Feng;Ou, Yongxi;Buhrman, R. A.
我们报告说，通过施加在FM上的自旋扭矩测量的Pt/铁磁体（FM）界面上的自旋电流传输强烈依赖于FM层的类型和厚度以及沉积后处理协议。通过采用谐波电压测量和自旋力矩铁磁共振测量，我们发现，Pt自旋霍尔效应的效率施加dampinglike自旋力矩FM对应于一个有效的自旋霍尔比范围从0.10在不同的界面条件下。在这项研究中使用的Pt薄膜的“内部”自旋霍尔比，考虑到界面自旋传输因子后，估计是类似于0.30。这表明Pt/FM界面的精心设计可以提高Pt基自旋电子器件的自旋霍尔扭矩效率。我们还注意到，两个矢量分量的自旋霍尔扭矩对温度的依赖性是强烈依赖于Pt/FM接口的细节，作为FM层厚度的函数的磁阻尼的测量通常是不可靠的，用于确定真正的有效自旋混合电导的接口。
We report that spin current transport across Pt/ferromagnet (FM) interfaces as measured by the spin torques exerted on the FM is strongly dependent on the type and the thickness of the FM layer and on post-deposition processing protocols. By employing both harmonic voltage measurements and spin-torque ferromagnetic resonance measurements, we find that the efficiency of the Pt spin Hall effect in exerting a dampinglike spin torque on the FM corresponds to an effective spin Hall ratio ranging from 0.10 under different interfacial conditions. The "internal" spin Hall ratio of the Pt thin films used in this study, after taking the interfacial spin transmission factor into account, is estimated to be similar to 0.30. This suggests that a careful engineering of Pt/FM interfaces can improve the spin Hall torque efficiency of Pt-based spintronic devices. We also note that the dependence on temperature for both vector components of the spin Hall torque is strongly dependent on the details of the Pt/FM interface, and that measurements of magnetic damping as a function of FM layer thickness are not generally reliable for determining the true effective spin mixing conductance for the interface.