Field-Free Perpendicular Magnetization Switching of SOT-MRAM Devices by Magnetic Spin Hall Effect

Spin-orbit torque magnetoresistive random access memory (SOT-MRAM) devices take advantage of the current induced SOTs mainly generated through the spin Hall effect (SHE) in order to achieve sub-ns switching speed and high endurance. However, to achieve deterministic switching of magnetic layers with an initial perpendicular magnetization, an external magnetic field is necessary. The magnetic spin Hall effect (MSHE) in antiferromagnets can be utilized to overcome this limitation and achieve field-free SOT switching. We employ a fully three-dimensional model coupling charge, spin and magnetization dynamics to study the switching behavior of SOT-MRAM devices. SOTs are included by considering the charge-to-spin current transversion coefficients reported for Mn
3
Sn and MnPd
3
antiferromagnets. We demonstrate the generation of out-of-plane spin current by in-plane charge current due to MSHE in a magnetic tunnel junction (MTJ). The spin current drives out-of-plane anti-damping-like torques leading to deterministic switching of the adjacent perpendicularly magnetized CoFeB magnetic free layer. The proposed device requires no external magnetic field and lower current densities, compared to conventional SHE-driven SOT-devices.