Brownian Motion and Entropic Torque Driven Motion of Domain-Wall in Antiferromagnets

TL;DR

This paper investigates how entropic torque and Brownian motion influence domain-wall dynamics in antiferromagnetic nanowires under temperature gradients, providing detailed conditions for their effects and implications for spintronics.

Contribution

It offers a detailed analysis of domain-wall motion driven by entropic torque and Brownian motion in antiferromagnets, clarifying conditions and effects not fully addressed in prior studies.

Findings

Domain-wall moves towards hotter or colder regions depending on dominant forces.

Anisotropy and temperature gradient can tune spin dynamics effectively.

Provides concrete conditions for entropic torque and Brownian motion influence.

Abstract

We study the spin dynamics in antiferromagnetic nanowire under an applied temperature gradient using micromagnetic simulations on a classical spin model with a uniaxial anisotropy. The entropic torque driven domain-wall motion and the Brownian motion are discussed in detail, and their competition determines the antiferromagnetic wall motion towards the hotter or colder region. Furthermore, the spin dynamics in an antiferromagnet can be well tuned by the anisotropy and the temperature gradient. Thus, this paper not only strengthens the main conclusions obtained in earlier works [Kim et al., Phys. Rev. B 92, 020402(R) (2015); Selzer et al., Phys. Rev. Lett. 117, 107201 (2016)], but more importantly gives the concrete conditions under which these conclusions apply, respectively. Our results may provide useful information on the antiferromagnetic spintronics for future experiments and storage device design.