Lack of correlation between the spin-mixing conductance and the inverse spin Hall effect generated voltages in CoFeB/Pt and CoFeB/Ta bilayers
Lack of correlation between the spin-mixing conductance and the inverse spin Hall effect generated voltages in CoFeB/Pt and CoFeB/Ta bilayers
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DOI：
10.1103/physrevb.95.174426
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发表时间：
2017-05-18
影响因子：
3.7
通讯作者：
Hillebrands, B.
中科院分区：
文献类型：
--
作者：
Conca, A.;Heinz, B.;Hillebrands, B.
我们研究了CoFeB/Pt和CoFeB/Ta多晶双层中的自旋泵现象，以及有效自旋混合电导率g(eff)（上下箭头）与Pt和Ta层中通过逆自旋霍尔效应将自旋转换为电荷电流所产生的电压之间的相关性。为此，我们测量了产生的电压对外部静磁场的面内角依赖性，并应用一个模型将自旋泵浦信号与磁层中自旋整流效应产生的信号分离开来。我们的研究结果揭示了异常霍尔效应对CoFeB自旋整流效应的主导作用，以及g(eff)（上下箭头）和逆自旋霍尔电压之间缺乏相关性，这表明Pt中的磁邻近效应在理解所观察到的阻尼增加方面发挥了重要作用。这也反映在吉尔伯特阻尼参数对铂厚度的线性依赖性上。
We investigate spin pumping phenomena in polycrystalline CoFeB/Pt and CoFeB/Ta bilayers and the correlation between the effective spin-mixing conductance g(eff)(up down arrow) and the obtained voltages generated by the spin-to-charge current conversion via the inverse spin Hall effect in the Pt and Ta layers. For this purpose, we measure the in-plane angular dependence of the generated voltages on the external static magnetic field and we apply a model to separate the spin pumping signal from the one generated by the spin rectification effect in the magnetic layer. Our results reveal a dominating role of anomalous Hall effect for the spin rectification effect with CoFeB and a lack of correlation between g(eff)(up down arrow) and inverse spin Hall voltages pointing to a strong role of the magnetic proximity effect in Pt in understanding the observed increased damping. This is additionally reflected on the presence of a linear dependency of the Gilbert damping parameter on the Pt thickness.