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

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.