Variation of spin-orbit torque and spin transport properties by V alloying in beta-W-based magnetic heterostructures

Abstract

Of transition metals, beta-W exhibits the maximum charge-to-spin conversion efficiency. However, due to the lack of phase stability, the beta-W-based alloy has rarely been investigated as a spin current generating layer. This study examines W-V alloy layers with various W100-xVx/CoFeB/MgO/Ta heterostructure compositions. X-ray diffraction confirms that the beta-W matrix is conserved up to a V content of 20 at%. We attain a maximum damping-like torque efficiency of - 0.45 +/- 0.04 for the W80V20 alloy-based heterostructure through the harmonic response method. Furthermore, we determine the spin diffusion length of the W80V20 layer and specify the interfacial spin transparency of the W80V20/CoFeB structure by adopting the spin diffusion model. Consequently, we suggest an intrinsic spin-Hall angle of -0.86. In addition, we observe in-plane current-induced switching. Our results establish the potential of the beta-phase W-V alloy layer as a spin current source layer in spintronic devices. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.