Observation of current-induced switching in non-collinear antiferromagnetic IrMn$_3$ by differential voltage measurements

TL;DR

This study demonstrates a novel experimental protocol to clearly distinguish magnetic from non-magnetic current-induced switching signals in antiferromagnetic IrMn$_3$/Pt devices, confirming magnetic switching through differential voltage measurements and micromagnetic simulations.

Contribution

The paper introduces a new experimental method using differential voltage measurements to unambiguously identify magnetic switching in AFM/HM structures, addressing previous interpretation challenges.

Findings

Reversible magnetic switching observed only when current passes through the IrMn$_3$ pillar.

The protocol effectively eliminates non-magnetic switching artifacts.

Micromagnetic simulations reveal a complex domain-mediated switching process.

Abstract

There is accelerating interest in developing memory devices using antiferromagnetic (AFM) materials, motivated by the possibility for electrically controlling AFM order via spin-orbit torques, and its read-out via magnetoresistive effects. Recent studies have shown, however, that high current densities create non-magnetic contributions to resistive switching signals in AFM/heavy metal (AFM/HM) bilayers, complicating their interpretation. Here we introduce an experimental protocol to unambiguously distinguish current-induced magnetic and nonmagnetic switching signals in AFM/HM structures, and demonstrate it in IrMn$_3$/Pt devices. A six-terminal double-cross device is constructed, with an IrMn$_3$ pillar placed on one cross. The differential voltage is measured between the two crosses with and without IrMn$_3$ after each switching attempt. For a wide range of current densities, reversible switching is observed only when write currents pass through the cross with the IrMn$_3$ pillar, eliminating any possibility of non-magnetic switching artifacts. Micromagnetic simulations support our findings, indicating a complex domain-mediated switching process.