# Magneto-Optical Detection of the Spin Hall Effect in Pt and W Thin Films

## TL;DR

This study uses magneto-optical Kerr microscopy to measure spin accumulation caused by the spin Hall effect in Pt and W thin films, providing quantitative insights into spin diffusion lengths and interfacial effects.

## Contribution

It introduces a magneto-optical detection method for spin Hall-induced spin accumulation and quantitatively compares experimental results with ab-initio calculations.

## Key findings

- Opposite Kerr rotation signs in Pt and W.
- Linear scaling of Kerr rotation with current density.
- Determined spin diffusion length in Pt as 11 ± 3 nm.

## Abstract

Here we report the measurement of the interfacial spin accumulation induced by the spin Hall effect in Pt and W thin films using magneto-optical Kerr microscopy. We show that the Kerr rotation has opposite sign in Pt and W and scales linearly with current density. By comparing the experimental results with ab-initio calculations of the spin Hall and magneto-optical Kerr effects, we quantitatively determine the current-induced spin accumulation at the Pt interface as $5*10^{-12} \mu_B$A$^{-1}$cm$^2$ per atom. From thickness-dependent measurements, we determine the spin diffusion length in a single Pt film to be $11 \pm 3$ nm, which is significantly larger compared to that of Pt adjacent to a magnetic layer.