Spin-wave contributions to current-induced domain wall dynamics

TL;DR

This paper theoretically investigates how spin-waves influence current-driven domain wall motion in ferromagnetic wires, revealing damping effects, modifications to domain wall properties, and temperature-dependent behaviors.

Contribution

It introduces a theoretical framework analyzing spin-wave interactions with domain walls, highlighting their impact on damping, width, mass, and temperature dependence in current-induced dynamics.

Findings

Spin-wave emission causes damping of domain wall motion.

Interaction modifies domain wall width and mass.

Coupling leads to temperature-dependent effective mass.

Abstract

We examine theoretically the role of spin-waves on current-induced domain wall dynamics in a ferromagnetic wire. At room temperature, we find that an interaction between the domain wall and the spin waves appears when there is a finite difference between the domain wall velocity $\dot{x}_0$ and the spin current $u$. Three important consequences of this interaction are found. Firstly, spin-wave emission leads to a Landau-type damping of the current-induced domain wall motion towards restoring the solution $\dot{x}_0 = u$, where spin angular momentum is perfectly transfered from the conduction electrons to the domain wall. Secondly, the interaction leads to a modification of the domain wall width and mass, proportional to the kinetic energy of the domain wall. Thirdly, the coupling by the electrical current between the domain wall and the spin waves leads to temperature-dependent effective wall mass.