📝 SummarXiv

Abstract

In spintronics, the spin Hall effect has been widely used to generate and detect spin currents in materials with strong spin-orbit coupling such as Pt and Ta. Recently, its orbital counterpart has drawn attention as a new tool to generate and detect orbital currents and thus investigate orbital transport parameters. In this study, we investigate vanadium (V), a $3d$ transition metal with weak spin-orbit coupling but with a theoretically large orbital Hall conductivity. We measure a large Hanle magnetoresistance in V thin films with a magnitude comparable to that of heavy metals and at least one order of magnitude higher than the spin Hall magnetoresistance observed in a Y$_3$Fe$_5$O$_{12}$/V bilayer, pointing to the orbital Hall origin of the effect. A fit of the magnetic-field dependence and thickness dependence of the Hanle magnetoresistance to the standard diffusion model allows us to quantify the orbital diffusion length (~2 nm) and the orbital Hall conductivity (~78 ($\hbar/2e$) $\Omega^{-1}$cm$^{-1}$) of V. The obtained orbital Hall conductivity is two orders of magnitude smaller than theoretical calculations of the intrinsic value, suggesting there is an important role of disorder.