Controlling spin supercurrents via nonequilibrium spin injection

TL;DR

This paper introduces a method to control spin supercurrents in superconductor/ferromagnet systems through nonequilibrium spin injection, revealing a new out-of-equilibrium spin supercurrent component with potential applications.

Contribution

It demonstrates how nonequilibrium spin injection can manipulate and generate additional spin supercurrents in superconductor/ferromagnet proximity systems, a novel physical effect.

Findings

Spin supercurrents can be controlled via nonequilibrium spin injection.

A new out-of-equilibrium spin supercurrent component is identified.

The effect is relevant for future spintronic applications.

Abstract

We propose a mechanism whereby spin supercurrents can be manipulated in superconductor/ferromagnet proximity systems via nonequilibrium spin injection. We find that if a spin supercurrent exists in equilibrium, a nonequilibrium spin accumulation will exert a torque on the spins transported by this current. This interaction causes a new spin supercurrent contribution to manifest out of equilibrium, which is proportional to and polarized perpendicularly to both the injected spins and equilibrium spin current. This is interesting for several reasons: as a fundamental physical effect; due to possible applications as a way to control spin supercurrents; and timeliness in light of recent experiments on spin injection in proximitized superconductors.