Spin flip scattering at Al surfaces

TL;DR

This study investigates how surface scattering affects spin relaxation in aluminum films, finding that surface-induced spin flip scattering is weaker than bulk scattering, with impurity effects dominating at low temperatures.

Contribution

It provides in-situ measurements of spin relaxation contributions from surface and bulk scattering in Al films, highlighting the weak role of surface spin flip scattering.

Findings

Surface scattering contributes less to spin relaxation than bulk scattering.

Impurity scattering dominates spin relaxation at low temperatures.

Spin diffusion length varies with film thickness and temperature.

Abstract

Non-local measurements are performed on a multi terminal device to $in-situ$ determine the spin diffusion length and in combination with resistivity measurements also the spin relaxation time in Al films. By varying the thickness of Al we determine the contribution to spin relaxation from surface scattering. From the temperature dependence of the spin diffusion length it is established that the spin relaxation is impurity dominated at low temperature. A comparison of the spin and momentum relaxation lengths for different thicknesses reveals that the spin flip scattering at the surfaces is weak compared to that within the bulk of the Al films.