Hydrogen-modified inverse Spin Hall Effect in palladium-cobalt bi-layer films

The influence of hydrogen gas absorption by the Pd layer of bi-layered films containing Pd and Co layers on the inverse Spin Hall Effect (iSHE) in the material is measured. iSHE is driven by ferromagnetic resonance in the cobalt layer. In these conditions, the iSHE is seen as a d.c. voltage across the Pd layer. In the presence of hydrogen gas the iSHE peak shifts downwards in the applied field together with the ferromagnetic resonance absorption peak for the material. In parallel, an increase in the iSHE peak height and in its width is observed. Our analysis suggests that these observations can potentially be explained as a reduction in the spin Hall angle for the Palladium layer in the presence of hydrogen gas.