Micromagnetic analysis and optimization of spin-orbit torque switching processes in synthetic antiferromagnets

Abstract

Based on micromagnetic simulations, we show that it is possible to achieve spin–orbit torque field-free switching of a synthetic antiferromagnet comprised of two ferromagnetic layers with perpendicular magnetic anisotropy, sitting on top of a conventional antiferromagnet. Field-free magnetization reversal is propelled by the competing exchange fields and spin torques. Although some antiferromagnetic coupling is necessary to switch both ferromagnetic layers, strong Ruderman-Kittel-Kasuya-Yosida inhibits the switching process due to the strong repelling forces experienced by both FM layers. The switching happens through domain nucleation and propagation and is aided by Dzyaloshinskii–Moriya interactions. The overall heterostructure is applicable in conjunction with a magnetic tunnel junction, where the free layer is comprised of the proposed synthetic antiferromagnet.