Spin-orbit torque in MgO/CoFeB/Ta/CoFeB/MgO symmetric structure with interlayer antiferromagnetic coupling

TL;DR

This paper investigates spin-orbit torque effects in a symmetric MgO/CoFeB/Ta/CoFeB/MgO structure with interlayer antiferromagnetic coupling, demonstrating simultaneous switching of two magnetic layers and potential for low-power magnetic memory devices.

Contribution

It introduces a novel study of spin-orbit torque in a symmetric multilayer with interlayer antiferromagnetic coupling, combining experimental observations with theoretical modeling.

Findings

Simultaneous switching of two CoFeB layers between antiparallel states.

Theoretical modeling confirms experimental results using Stoner-Wohlfarth and LLG equations.

Potential for magnetic memories with low stray field and low power consumption.

Abstract

Spin current generated by spin Hall effect in the heavy metal would diffuse up and down to adjacent ferromagnetic layers and exert torque on their magnetization, called spin-orbit torque. Antiferromagnetically coupled trilayers, namely the so-called synthetic antiferromagnets (SAF), are usually employed to serve as the pinned layer of spintronic devices based on spin valves and magnetic tunnel junctions to reduce the stray field and/or increase the pinning field. Here we investigate the spin-orbit torque in MgO/CoFeB/Ta/CoFeB/MgO perpendicularly magnetized multilayer with interlayer antiferromagnetic coupling. It is found that the magnetization of two CoFeB layers can be switched between two antiparallel states simultaneously. This observation is replicated by the theoretical calculations by solving Stoner-Wohlfarth model and Landau-Lifshitz-Gilbert equation. Our findings combine spin-orbit torque and interlayer coupling, which might advance the magnetic memories with low stray field and low power consumption.