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

Spin current generated by the spin Hall effect in a heavy metal that would diffuse up and down to adjacent ferromagnetic layers and exert torque on their magnetization is called spin-orbit torque. Antiferromagnetically coupled trilayers, namely, the so-called synthetic antiferromagnets usually are 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 a 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 the Stoner-Wohlfarth model and the Landau-Lifshitz- Gilbert equation. Our findings combine spin-orbit torque and interlayer coupling, which might advance the magnetic memories with a low stray field and low power consumption.