Domain-wall depinning assisted by pure spin currents

TL;DR

This paper demonstrates that pure spin currents can efficiently depin magnetic domain walls, with an efficiency surpassing traditional current-induced methods, supported by experimental measurements and theoretical modeling.

Contribution

It introduces a novel method of domain-wall depinning using pure spin currents and quantifies its high efficiency through experiments and theory.

Findings

Spin currents induce domain-wall depinning with high efficiency.

Depinning efficiency exceeds that of conventional current methods.

Theoretical model explains surface torque mechanism.

Abstract

We study the depinning of domain walls by pure diffusive spin currents in a nonlocal spin valve structure based on two ferromagnetic permalloy elements with copper as the nonmagnetic spin conduit. The injected spin current is absorbed by the second permalloy structure with a domain wall and from the dependence of the wall depinning field on the spin current density we find an efficiency of 6*10^{-14}T/(A/m^2), which is more than an order of magnitude larger than for conventional current induced domain wall motion. Theoretically we reproduce this high efficiency, which arises from the surface torques exerted by the absorbed spin current that lead to efficient depinning.