Manipulation of Inverse Spin Hall Effect in Palladium by Absorption of Hydrogen Gas

TL;DR

This study investigates how hydrogen gas absorption affects the inverse spin Hall effect in palladium thin films, revealing a decrease in spin diffusion length but unchanged spin Hall conductivity.

Contribution

It provides the first detailed analysis of hydrogen's impact on spin transport properties in palladium using cavity ferromagnetic resonance.

Findings

Hydrogen absorption reduces ISHE voltage amplitude.

Spin diffusion length decreases by 23% with hydrogen.

Spin Hall conductivity remains unchanged.

Abstract

The spintronic properties of a palladium thin film have been investigated in the presence of hydrogen gas in cobalt/palladium bilayers. Measurements of the inverse spin Hall Effect (ISHE) using cavity ferromagnetic resonance allow estimations of the spin Hall conductivity and spin diffusion length in both nitrogen and hydrogen gas atmospheres. Unwanted spin rectification effects are removed using a simple method of inverting the spin current direction with respect to the measurement setup. Absorption of hydrogen gas in the Pd layer at just 3% concentration results in a reduced ISHE voltage amplitude and bilayer resistance. Fitting the ISHE voltage against the Pd layer thickness demonstrates that the spin diffusion length decreases by 23% in the presence of a hydrogen gas. On the other hand, the results indicate that there is no significant change in the spin Hall conductivity of Pd due to hydrogen absorption.