Near-unity spin Hall ratio in Ni Cu alloys.

We report a large spin Hall effect in the 3 transition metal alloy Ni Cu for ∈ {0.3, 0.75}, detected via the ferromagnetic resonance of a permalloy (Py = NiFe) film deposited in a bilayer with the alloy. A thickness series at = 0.6, for which the alloy is paramagnetic at room temperature, allows us to determine the spin Hall ratio ≈ 1, spin diffusion length λ, spin mixing conductance , and damping due to spin memory loss α. We compare our results with similar experiments on Py/Pt bilayers measured using the same method. band structure calculations with disorder and spin-orbit coupling suggest an intrinsic spin Hall effect in Ni Cu alloys, although the experiments here cannot distinguish between extrinsic and intrinsic mechanisms.