Magnetic-Field-Driven Antiferromagnetic Domain Wall Motion

TL;DR

This paper presents a theoretical framework for antiferromagnetic domain wall motion driven by inhomogeneous magnetic fields, highlighting a paramagnetic response and Stern-Gerlach-like force, with validation from atomistic simulations.

Contribution

It introduces a new theoretical model describing antiferromagnetic domain wall motion under inhomogeneous fields, including effects of pinning and reformulation without intrinsic magnetization.

Findings

Domain wall motion initiated by paramagnetic response.

Agreement with atomistic simulation results.

Analysis of pinning potential effects.

Abstract

We theoretically study the antiferromagnetic domain wall motion actuated by an inhomogeneous external magnetic field. The Lagrangian and the equations of motion of antiferromagnetic spins under an inhomogeneous magnetic field are derived, first in terms of the N\'eel vector, and then using collective coordinates of the domain wall. A solution is found that describes the actuation of a domain wall by an inhomogeneous field, in which the motion is initiated by a paramagnetic response of wall magnetization, which is then driven by a Stern-Gerlach like force. The effects of pinning potential are also investigated. These results are in good agreement with atomistic simulations. While the present formulation contains the so-called intrinsic magnetization associated with N\'eel texture, a supplementary discussion is given to reformulate the theory in terms of physical magnetization without the intrinsic magnetization.