Tuning the spin Hall effect of Pt from the moderately dirty to the superclean regime

Abstract

The discovery of new spin-to-charge current conversion effects such as the spin Hall effect (SHE) is expanding the potential of spintronic applications. In contrast to the anomalous Hall effect (AHE), a systematic experimental study of the different mechanisms contributing to the SHE is lacking. Finding routes to maximize the SHE is not possible as long as it remains unclear which is the dominant mechanism in a material. The authors systematically study Pt, the prototypical SHE material, using the spin absorption method and find a single intrinsic spin Hall conductivity in a wide range of Pt conductivities, in good agreement with theory. By tuning the conductivity, they observe for the first time the crossover between the moderately dirty and the superclean scaling regimes of the SHE, equivalent to that obtained for the AHE. These results explain the dispersion of values in the literature and show a clear path to enhance this important effect.