Extrinsic Spin Hall effect of AuW alloys

The spin Hall effect (SHE) allows a reciprocal conversion between charge and spin currents using spin orbit interactions. Large Spin Hall angle have been reported in transition metals (Pt, W, Beta-Ta) and in alloys made of heavy metals [1]. We will report on SHA in AuW alloys [2] exhibiting a non-monotonic relation with W content. In this regime, it suggests a skew-scattering to side-jump dominant contribution to the spin Hall resistivity, thus allowing precise tuning of SHA vs. W content. We will present experiments by using Lateral Spin Valves with refined spin-absorption model adapted to strong spin-orbit interactions. By using complementary FMR/Spin-Pumping techniques, we demonstrate very large SHA of the order of 15~{\%} at rather high W concentration in rather good agreement with the previous method. [1] \textit{PRL} \textbf{109, }156602 (2012), \textit{PRB} \textbf{89,} 054401 (2014), [2] P. Laczkowski \textit{et al.}, \textit{APL} \textbf{104}, 142403 (2014) .