Ultralow-loss domain wall motion driven by magnetocrystalline anisotropy gradient in antiferromagnetic nanowire

TL;DR

This paper proposes a theoretical method to control antiferromagnetic domain wall motion using an electric field-induced anisotropy gradient, enabling ultra-low energy loss operation for spintronic devices.

Contribution

It introduces a novel approach to manipulate AFM domain walls via anisotropy gradients, with detailed simulations and physical explanations of the dynamics involved.

Findings

Domain wall velocity increases with anisotropy gradient.

Mobility is unaffected by lattice type but enhanced by Dzyaloshinskii-Moriya interaction.

Faster AFM wall dynamics compared to ferromagnetic walls explained.

Abstract

Searching for new methods controlling antiferromagnetic (AFM) domain wall is one of the most important issues for AFM spintronic device operation. In this work, we study theoretically the domain wall motion of an AFM nanowire, driven by the axial anisotropy gradient generated by external electric field, allowing the electro control of AFM domain wall motion in the merit of ultra-low energy loss. The domain wall velocity depending on the anisotropy gradient magnitude and intrinsic material properties is simulated based on the Landau-Lifshitz-Gilbert equation and also deduced using the energy dissipation theorem. It is found that the domain wall moves at a nearly constant velocity for small gradient, and accelerates for large gradient due to the enlarged domain wall width. The domain wall mobility is independent of lattice dimension and types of domain wall, while it is enhanced by the Dzyaloshinskii-Moriya interaction. In addition, the physical mechanism for much faster AFM wall dynamics than ferromagnetic wall dynamics is qualitatively explained. This work unveils a promising strategy for controlling the AFM domain walls, benefiting to future AFM spintronic applications.