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

TL;DR

This paper presents a new analytical model for accurately determining the spin diffusion length of AuW alloys, accounting for spin-current polarization and accumulation effects, crucial for spin Hall angle estimation.

Contribution

It introduces an analytical model supported by numerical calculations that improves the extraction of spin diffusion lengths in materials with strong spin-orbit interactions.

Findings

Width variations drastically affect spin absorption in AuW stripes.

Conventional analysis fails to explain the observed changes.

The new model accurately estimates the spin diffusion length.

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.