Enhancement of spin Hall conductivity in W–Ta alloy
Enhancement of spin Hall conductivity in W–Ta alloy
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DOI：
10.1063/5.0022012
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
Jun-Young Kim;Dong-Soo Han;M. Vafaee;S. Jaiswal;Kyujoon Lee;G. Jakob;M. Kläui
中科院分区：
文献类型：
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作者：
Jun-Young Kim;Dong-Soo Han;M. Vafaee;S. Jaiswal;Kyujoon Lee;G. Jakob;M. Kläui
通过重金属中的自旋霍尔效应产生纯自旋电流是近十年来的一个活跃的研究课题。为了减少有效地切换相邻铁磁层以用于应用所需的能量，不仅应该增加电荷-自旋转换效率，而且还应该降低重金属的纵向电阻率。本文利用自旋矩铁磁共振测量方法研究了W_{1-x}Ta_{x} / CoFeB / MgO（x = 0 - 0.2）体系的自旋霍尔电导。W与Ta的合金化导致阻尼类有效自旋霍尔角（从-0.15到-0.3）和纵向电阻率（60 - 120 W cm）的两个变化因子。在11%的Ta浓度，一个非常高的自旋霍尔角值为-0.3实现了低纵向电阻率100 {\mu}W cm，这可能会导致一个非常低的功耗，这种W基合金。这项工作表明，电沉积的W-Ta合金可能是一种有前途的材料，用于功率高效的自旋电流产生。
Generating pure spin currents via the spin Hall effect in heavy metals has been an active topic of research in the last decade. In order to reduce the energy required to efficiently switch neighbouring ferromagnetic layers for applications, one should not only increase the charge- to-spin conversion efficiency but also decrease the longitudinal resistivity of the heavy metal. In this work, we investigate the spin Hall conductivity in W_{1-x}Ta_{x} / CoFeB / MgO (x = 0 - 0.2) using spin torque ferromagnetic resonance measurements. Alloying W with Ta leads to a factor of two change in both the damping-like effective spin Hall angle (from - 0.15 to - 0.3) and longitudinal resistivity (60 - 120 {\mu}W cm). At 11% Ta concentration, a remarkably high spin Hall angle value of - 0.3 is achieved with a low longitudinal resistivity 100 {\mu}W cm, which could lead to a very low power consumption for this W-based alloy. This work demonstrates sputter-deposited W-Ta alloys could be a promising material for power-efficient spin current generation.