Temperature study of the giant spin Hall effect in the bulk limit of β−W

Abstract

Giant spin Hall effect (GSHE) in heavy metals can convert charge current into spin current with a high efficiency characterized by a spin Hall angle. In this paper, we prepare a set of multilayer systems of $\ensuremath{\beta}\ensuremath{-}\mathrm{W}$/CoFeB/MgO/Ta with the different $\ensuremath{\beta}\ensuremath{-}\mathrm{W}$ thickness up to 18 nm. Using a direct-current magneto-transport method and relying on the anomalous Hall effect of CoFeB, we observed a large spin Hall angle of 64% in the bulk limit of $\ensuremath{\beta}\ensuremath{-}\mathrm{W}$ solid at room temperature and a weak temperature dependence of the spin Hall angle. Additionally, we also studied the crystal structure, magnetization, magnetic anisotropy, electrical transport, spin diffusion, and interfacial spin current transmission in this exemplary GSHE system over a broad temperature range of 10 to 300 K, which would benefit fundamental studies and potential spintronics applications of $\ensuremath{\beta}\ensuremath{-}\mathrm{W}$.