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.