Experimental study of extrinsic spin Hall effect in CuPt alloy

TL;DR

This study experimentally investigates how adding platinum to copper influences the spin Hall effect, revealing that even low Pt concentrations significantly enhance the spin Hall angle, with implications for spintronic device integration.

Contribution

It provides systematic experimental data on the relationship between Pt concentration and spin Hall effects in CuPt alloys, highlighting their potential for spintronic applications.

Findings

Spin Hall angle increases with Pt concentration.

28% Pt in CuPt yields a spin Hall angle comparable to pure Pt.

Skew scattering dominates at low Pt, side-jump at high Pt.

Abstract

We have experimentally studied the effects on the spin Hall angle due to systematic addition of Pt into the light metal Cu. We perform spin torque ferromagnetic resonance measurements on Py/CuPt bilayer and find that as the Pt concentration increases, the spin Hall angle of CuPt alloy increases. Moreover, only 28% Pt in CuPt alloy can give rise to a spin Hall angle close to that of Pt. We further extract the spin Hall resistivity of CuPt alloy for different Pt concentrations and find that the contribution of skew scattering is larger for lower Pt concentrations, while the side-jump contribution is larger for higher Pt concentrations. From technological perspective, since the CuPt alloy can sustain high processing temperatures and Cu is the most common metallization element in the Si platform, it would be easier to integrate the CuPt alloy based spintronic devices into existing Si fabrication technology.