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arXiv · 1208.1711

Spin transfer torque devices utilizing the giant spin Hall effect of tungsten

Chi-Feng Pai·Luqiao Liu·Y. Li·H. W. Tseng·D. C. Ralph·R. A. Buhrman
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Abstract

We report a giant spin Hall effect (SHE) in {\beta}-W thin films. Using spin torque induced ferromagnetic resonance with a {\beta}-W/CoFeB bilayer microstrip we determine the spin Hall angle to be |\theta|=0.30\pm0.02, large enough for an in-plane current to efficiently reverse the orientation of an in-plane magnetized CoFeB free layer of a nanoscale magnetic tunnel junction adjacent to a thin {\beta}-W layer. From switching data obtained with such 3-terminal devices we independently determine |\theta|=0.33\pm0.06. We also report variation of the spin Hall switching efficiency with W layers of different resistivities and hence of variable ({\alpha} and {\beta}) phase composition.

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Chi-Feng Pai, Luqiao Liu, Y. Li, H. W. Tseng, D. C. Ralph, R. A. Buhrman. 2012-08-08. Spin transfer torque devices utilizing the giant spin Hall effect of tungsten. https://doi.org/10.1063/1.4753947

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