Voltage-induced high-speed DW motion in a synthetic antiferromagnet

TL;DR

This paper demonstrates that voltage-induced domain wall motion in a synthetic antiferromagnet can achieve high speeds due to strong interlayer coupling, overcoming limitations seen in single ferromagnetic layers.

Contribution

The study introduces a high-speed voltage-induced domain wall motion mechanism in synthetic antiferromagnets, highlighting the role of interlayer exchange coupling in enhancing velocity.

Findings

High DW velocity in SAF compared to single layers

Interlayer antiferromagnetic exchange coupling inhibits tilting and Walker breakdown

Voltage-induced magnetic anisotropy gradient acts as an effective driving field

Abstract

Voltage-induced motion of a magnetic domain wall (DW) has potential in developing novel devices with ultralow dissipation. However, the speed for the voltage-induced DW motion (VIDWM) in a single ferromagnetic layer is usually very low. In this work, we proposed VIDWM with high speed in a synthetic antiferromaget (SAF). The velocity for the coupled DWs in the SAF is significantly higher than its counterpart in a single ferromagnetic layer. Strong interlayer antiferromagnetic exchange coupling plays a critical role for the high DW velocity since it inhibits the tilting of DW plane with strong Dzyaloshinskii-Moriya interaction. On the other hand, the Walker breakdown of DW motion is also inhibited due to the stabilization of moment orientation under a strong interlayer antiferromagnetic coupling. In theory, the voltage-induced gradient of magnetic anisotropy is proved to be equal to an effective magnetic field that drives DW.