Current-induced Vortex Motion by Spin-Transfer Torque

TL;DR

This paper analyzes how spin-transfer torque induces vortex motion in magnetic nanodots, revealing a Lorentz-like force linked to topological properties, and proposes an experiment to observe this effect.

Contribution

It provides an analytical and numerical study of vortex dynamics driven by spin current, highlighting the topological and geometric nature of the forces involved.

Findings

Vortex core experiences a transverse force proportional to spin current.

The force is interpreted as a reaction of Lorentz-type force from conduction electrons.

An experimental setup is proposed to observe vortex displacement due to spin current.

Abstract

We investigate the dynamics of a magnetic vortex driven by spin-transfer torque due to spin current in the adiabatic case. The vortex core represented by collective coordinate experiences a transverse force proportional to the product of spin current and gyrovector, which can be interpreted as the geometric force determined by topological charges. We show that this force is just a reaction force of Lorentz-type force from the spin current of conduction electrons. Based on our analyses, we propose analytically and numerically a possible experiment to check the vortex displacement by spin current in the case of single magnetic nanodot.