Effect of the interface resistance in non-local Hanle measurements

TL;DR

This paper investigates how interface resistance affects the measurement of spin transport properties in non-local Hanle experiments using lateral spin valves, highlighting the complexities and sensitivities involved.

Contribution

It introduces a general expression accounting for interface resistance in spin injection and transport, and analyzes its impact on spin-diffusion length extraction.

Findings

Fitted spin-diffusion length agrees with standard measurements for finite interface resistance.

Transparent contacts show significant discrepancies in spin-diffusion length estimates.

Corrected models still exhibit deviations, especially at shorter channel distances.

Abstract

We use lateral spin valves with varying interface resistance to measure non-local Hanle effect in order to extract the spin-diffusion length of the non-magnetic channel. A general expression that describes spin injection and transport, taking into account the influence of the interface resistance, is used to fit our results. Whereas the fitted spin-diffusion length value is in agreement with the one obtained from standard non-local measurements in the case of a finite interface resistance, in the case of transparent contacts a clear disagreement is observed. The use of a corrected expression, recently proposed to account for the anisotropy of the spin absorption at the ferromagnetic electrodes, still yields a deviation of the fitted spin-diffusion length which increases for shorter channel distances. This deviation shows how sensitive the non-local Hanle fittings are, evidencing the complexity of obtaining spin transport information from such type of measurements.