Magnetoelectric domain wall dynamics and its implications for magnetoelectric memory

TL;DR

This paper analyzes the dynamics of magnetoelectric domain walls in antiferromagnets like Cr$_2$O$_3$ and explores their potential for high-density, programmable memory devices, highlighting how strain and device design can optimize performance.

Contribution

It introduces a method to enhance domain wall mobility in magnetoelectric antiferromagnets using strain and proposes a split-gate scheme for improved memory applications.

Findings

Maximum domain wall mobility occurs at specific electric fields due to gyrotropic coupling.

Applying in-plane shear strain significantly increases domain wall mobility.

A split-gate design can improve memory density and functionality.

Abstract

Domain wall dynamics in a magnetoelectric antiferromagnet is analyzed, and its implications for magnetoelectric memory applications are discussed. Cr$_2$O$_3$ is used in the estimates of the materials parameters. It is found that the domain wall mobility has a maximum as a function of the electric field due to the gyrotropic coupling induced by it. In Cr$_2$O$_3$ the maximal mobility of 0.1 m/(s$\times$Oe) is reached at $E\approx0.06$ V/nm. Fields of this order may be too weak to overcome the intrinsic depinning field, which is estimated for B-doped Cr$_2$O$_3$. These major drawbacks for device implementation can be overcome by applying a small in-plane shear strain, which blocks the domain wall precession. Domain wall mobility of about 0.7 m/(s$\times$Oe) can then be achieved at $E=0.2$ V/nm. A split-gate scheme is proposed for the domain-wall controlled bit element; its extension to multiple-gate linear arrays can offer advantages in memory density, programmability, and logic functionality.