Spin Hanle effect in mesoscopic superconductors

TL;DR

This paper theoretically investigates how superconductivity influences spin transport in mesoscopic spin valves, revealing conditions that enhance or suppress spin rotation and predicting a new subgap conductance effect that affects spin dynamics at low temperatures.

Contribution

It introduces a novel theoretical framework for understanding spin transport in superconducting mesoscopic structures, highlighting the impact of different spin relaxation mechanisms and predicting a new subgap conductance contribution.

Findings

Superconductivity can enhance or suppress spin rotation depending on relaxation mechanisms.

A new subgap contribution to nonlocal conductance is predicted.

Spin rotation effects are eliminated at low temperatures under certain conditions.

Abstract

We present a theoretical study of spin transport in a superconducting mesoscopic spin valve under the action of a magnetic field misaligned with respect to the injected spin. We demonstrate that superconductivity can either strongly enhance or suppress the coherent spin rotation depending on the type of spin relaxation mechanism being dominated either by spin-orbit coupling or spin-flip scattering at impurities. We also predict a hitherto unknown subgap contribution to the nonlocal conductance in multiterminal superconducting hybrid structures which completely eliminates the effect of spin rotation at sufficiently low temperatures.