Field-free spin orbit torque switching of synthetic antiferromagnet through interlayer Dzyaloshinskii-Moriya interaction

TL;DR

This paper demonstrates the theoretical and experimental realization of field-free spin orbit torque switching in synthetic antiferromagnets by leveraging interlayer Dzyaloshinskii-Moriya interaction, advancing spintronic memory technology.

Contribution

It introduces a novel method to achieve field-free SOT switching in SAFs through interlayer DMI, combining theoretical modeling and experimental validation.

Findings

Interlayer DMI exists in the SAF sample as confirmed by anomalous Hall measurements.

Field-free switching is successfully achieved in the SAF sample.

Switching speed increases with in-plane mirror asymmetry of injected spins.

Abstract

Perpendicular synthetic antiferromagnets (SAFs) are of interest for the next generation ultrafast, high density spintronic memory and logic devices. However, to energy efficiently operate their magnetic order by current-induced spin orbit torques (SOTs), an unfavored high external field is conventionally required to break the symmetry. Here, we theoretically and experimentally demonstrate the field-free SOT switching of a perpendicular SAF through the introduction of interlayer Dzyaloshinskii-Moriya interaction (DMI). By macro-spin simulation, we show that the speed of field-free switching increases with the in-plane mirror asymmetry of injected spins. We experimentally observe the existence of interlayer DMI in our SAF sample by an azimuthal angular dependent anomalous Hall measurement. Field-free switching is accomplished in such a sample and the strength of the effective switching field demonstrates its origin from interlayer DMI. Our results provide a new strategy for SAF based high performance SOT devices.