Enhanced spin-flip scattering at the surface of copper in lateral spin valves

TL;DR

This study investigates how surface spin-flip scattering affects spin transport in copper within lateral spin valves, revealing that surface effects dominate spin diffusion length and interface polarization.

Contribution

It introduces a modified spin-diffusion model highlighting surface and interface spin-flip scattering as key factors affecting spin transport in copper.

Findings

Spin diffusion length increases with Cu thickness.

Surface spin-flip scattering dominates Cu's spin diffusion.

Py interface polarization is reduced by interfacial spin-flip scattering.

Abstract

We performed non-local electrical measurements of a series of Py/Cu lateral spin valve devices with different Cu thicknesses. We show that both the spin diffusion length of Cu and the apparent spin polarization of Py increase with Cu thickness. By fitting the results to a modified spin-diffusion model, we show that the spin diffusion length of Cu is dominated by spin-flip scattering at the surface. In addition, the dependence of spin polarization of Py on Cu thickness is due to a strong spin-flip scattering at the Py/Cu interface.