Domain wall motion at low current density in a synthetic antiferromagnet nanowire

TL;DR

This study demonstrates that synthetic antiferromagnet nanowires enable faster domain wall motion at lower current densities, reducing energy consumption in spintronic racetrack memory devices.

Contribution

The paper provides experimental evidence that domain walls in synthetic antiferromagnets depin at lower currents and move faster than in conventional multilayers, highlighting their potential for low-energy spintronic applications.

Findings

DWs depin at approximately 3 x 10^{11} A/m^2.

DWs respond faster to short current pulses in SAF structures.

SAF structures are more energy-efficient for racetrack memory.

Abstract

The current-driven motion of magnetic domain walls (DWs) is the working principle of magnetic racetrack memories. In this type of spintronic technology, high current densities are used to propel DW motion in magnetic nanowires, causing significant wire heating. Synthetic antiferromagnets are known to show very fast DW motion at high current densities, but lower current densities around onset of motion have received less attention. Here we use scanning transmission x-ray microscopy to study the response of DWs in a SAF multilayer to currents. We observe that the DWs depin at $\sim 3 \times 10^{11}$~A/m$^2$ and move more quickly in response to 5~ns duration current pulses than in comparable conventional multilayers. The results suggest that DWs in SAF structures are superior to conventional N\'{e}el DWs for low energy consumption racetrack technologies.