Near-Unity Spin Hall Ratio in Ni_xCu_1-x Alloys

2019/03/31 by Mark W. Keller, Katy S. Gerace, Monika Arora +3 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevb.99.214411

published as Phys. Rev. B 99, 214411 (2019) · New ab initio calculations of Ni-Cu alloy band structure added; new author; new fig in main text and new appendix describing calculations

arxiv created 2019/04/10 · arxiv updated 2019/06/12

Abstract

We report a large spin Hall effect in the 3d transition metal alloy Ni_xCu_1-x for x∈\ 0.3,0.75\ , detected via the ferromagnetic resonance of a Permalloy (Py = Ni₈₀Fe₂₀) film deposited in a bilayer with the alloy. A thickness series at x = 0.6, for which the alloy is paramagnetic at room temperature, allows us to determine the spin Hall ratio θ_\rmSH≈1, spin diffusion length λ_\rms, spin mixing conductance G_{\uparrow\downarrow}, and damping α_\rmSML due to spin memory loss . We compare our results with similar experiments on Py/Pt bilayers measured using the same method. Ab initio band structure calculations with disorder and spin-orbit coupling suggest an intrinsic spin Hall effect in Ni_xCu_1-x alloys, although the experiments here cannot distinguish between extrinsic and intrinsic mechanisms.

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