Spin accumulation induced resistance in mesoscopic ferromagnet/ superconductor junctions

TL;DR

This paper investigates how spin-polarized transport in mesoscopic ferromagnet-superconductor junctions leads to a spin contact resistance due to Andreev reflection, with expressions derived for different device geometries.

Contribution

It provides a theoretical description of spin accumulation and contact resistance in diffusive F/S systems with transparent interfaces, including geometry-dependent effects.

Findings

Spin reversal causes excess spin density near F/S interface.

Contact resistance depends on magnetization orientation in four-terminal setups.

Expressions for contact resistance are derived for two-terminal and four-terminal geometries.

Abstract

We present a description of spin-polarized transport in mesoscopic ferromagnet-superconductor (F/S) systems, where the transport is diffusive, and the interfaces are transparent. It is shown that the spin reversal associated with Andreev reflection generates an excess spin density close to the F/S interface, which leads to a spin contact resistance. Expressions for the contact resistance are given for two terminal and four terminal geometries. In the latter the sign depends on the relative magnetization of the ferromagnetic electrodes.