Evaluation of the spin diffusion length of AuW alloy by spin absorption experiments in the limit of large spin-orbit interactions

Abstract

The knowledge of the spin diffusion length ${\lambda }_A$ is a prerequisite for the estimation of the spin Hall angle. We investigate spin current absorption of materials with small ${\lambda }_A$ using AuW stripes inserted in lateral spin-valves. Width variations of the AuW stripe lead to drastic changes of the spin absorption, which cannot be explained by conventional analysis. We show that the spin-current polarization and the spin accumulation attenuation in the vicinity of the spin absorber must to be precisely taken into account for accurate estimation of ${\lambda }_A$. We propose an analytical model supported by numerical calculations that allows to extract proper ${\lambda }_A$ values of spin Hall effect materials.