Ferromagnetic domain wall as a nonreciprocal string

TL;DR

This paper models a ferromagnetic domain wall as a nonreciprocal string with asymmetric wave propagation, revealing unique dynamics that align with numerical simulations of domain wall motion.

Contribution

It introduces a simple, parameterized model of a ferromagnetic domain wall as a nonreciprocal string, highlighting its unusual dynamics and agreement with simulations.

Findings

Nonreciprocal string model captures domain wall dynamics.

Asymmetric wave speeds in opposite directions.

Model parameters match numerical simulations.

Abstract

We present a simple model of a domain wall in a thin-film ferromagnet. A domain wall is represented as a nonreciprocal string, on which transverse waves propagate with different speeds in opposite directions. The model has three parameters: mass density, tension, and a gyroscopic constant quantifying the nonreciprocity. We discuss the unusual dynamics of a nonreciprocal string in finite geometry. It agrees well with numerically simulated motion of a ferromagnetic domain wall in a strip of constant width.