Current-spin coupling for ferromagnetic domain walls in fine wires

TL;DR

This paper investigates how electric currents interact with ferromagnetic domain walls in fine wires, demonstrating that current can induce uniform motion of the walls through angular momentum transfer, modeled by modified Landau-Lifshitz-Gilbert equations.

Contribution

It provides a theoretical analysis of current-induced domain wall motion, highlighting perfect angular momentum transfer and the resulting uniform movement without external potentials.

Findings

Current induces perfect angular momentum transfer to domain walls.

Domain walls move uniformly in the absence of symmetry-breaking potentials.

Modified Landau-Lifshitz-Gilbert equations describe the dynamics.

Abstract

The coupling between a current and a domain wall is examined. In the presence of a finite current and the absence of a potential which breaks the translational symmetry, there is a perfect transfer of angular momentum from the conduction electrons to the wall. As a result, the ground state is in uniform motion. This remains the case when relaxation is accounted for. This is described by, appropriately modified, Landau-Lifshitz-Gilbert equations.