Extrinsic Spin Hall Effect in Cu1-xPtx

We experimentally study 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 a Py/Cu1-xPtx bilayer and find that as the Pt concentration increases, the spin Hall angle of Cu1-xPtx increases. Moreover, only 28% Pt in Cu1-xPtx can give rise to a spin Hall angle close to that of Pt. We further extract the spin Hall resistivity of Cu1-xPtx 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 a technological perspective, since Cu1-xPtx can sustain high processing temperatures, and Cu is the most common metallization element in the Si platform, it is easier to integrate the Cu1-xPtx-based spintronic devices into existing Si fabrication technology.