Motion of domain walls and the dynamics of kinks in the magnetic Peierls potential

TL;DR

This paper investigates the motion of magnetic domain walls in the Peierls potential, revealing kink dynamics akin to sine-Gordon solitons and providing analytical and numerical insights into their behavior.

Contribution

It introduces a model for kink dynamics in magnetic domain walls within the Peierls potential, including analytical expressions and numerical simulations.

Findings

Kinks behave like sine-Gordon solitons in thin films.

Analytical expressions match numerical results for kink mass and velocity.

Long-lived breathers are observed in simulations.

Abstract

We study the dynamics of magnetic domain walls in the Peierls potential due to the discreteness of the crystal lattice. The propagation of a narrow domain wall (comparable to the lattice parameter) under the effect of a magnetic field proceeds through the formation of kinks in its profile. We predict that, despite the discreteness of the system, such kinks can behave like sine-Gordon solitons in thin films of materials such as yttrium iron garnets, and we derive general conditions for other materials. In our simulations we also observe long-lived breathers. We provide analytical expressions for the effective mass and limiting velocity of the kink in excellent agreement with our numerical results.