Extrinsic Spin Hall Effect Induced by Iridium Impurities in Copper

TL;DR

This paper demonstrates that Ir impurities in copper induce a significant extrinsic spin Hall effect, with a consistent spin Hall angle across various concentrations and temperatures, highlighting skew scattering as the main mechanism.

Contribution

It provides experimental evidence of extrinsic spin Hall effect in CuIr alloys, emphasizing the role of Ir impurities and skew scattering in nonmagnetic materials.

Findings

Spin Hall resistivity increases linearly with Ir concentration.

Spin Hall angle remains constant across temperature range.

Skew scattering dominates the extrinsic spin Hall effect in CuIr.

Abstract

We study the extrinsic spin Hall effect induced by Ir impurities in Cu by injecting a pure spin current into a CuIr wire from a lateral spin valve structure. While no spin Hall effect is observed without Ir impurity, the spin Hall resistivity of CuIr increases linearly with the impurity concentration. The spin Hall angle of CuIr, $(2.1 \pm 0.6)$% throughout the concentration range between 1% and 12%, is practically independent of temperature. These results represent a clear example of predominant skew scattering extrinsic contribution to the spin Hall effect in a nonmagnetic alloy.