Free-Layer-Thickness-dependence of the Spin Galvanic Effect with Spin Rotation Symmetry

TL;DR

This study investigates how the free-layer thickness influences the spin galvanic effect with spin rotation symmetry, revealing two contributing processes and estimating the spin diffusion length in Py.

Contribution

It identifies two distinct processes contributing to the effect and provides a quantitative estimate of the spin diffusion length in Py based on thickness dependence.

Findings

Two processes contribute to the spin galvanic effect with spin rotation symmetry.

The spin diffusion length of Py is estimated to be 3.9±0.2 nm.

The effect can be used to study the spin Seebeck effect in metallic magnetic films.

Abstract

Spin-orbit coupling near the surface of a ferromagnetic metal gives rises to spin-to-charge conversion with symmetry different from the conventional inverse spin Hall effect. We have previously observed this spin galvanic effect with spin rotation symmetry (SGE-SR) in a spin valve under a temperature gradient. Here we show there are two processes that contribute to the SGE-SR, one of which is sensitive to the free magnetic layer thickness, while the other only depends on the interface of the free layer. Based on the free-layer-thickness-dependent study, we extrapolate the spin diffusion length of Py to be 3.9+/-0.2 nm. We also propose that the SGE-SR can help to quantitatively study the spin Seebeck effect in metallic magnetic films.