Deterministic Switching of Perpendicularly Magnetic Layers by Spin–Orbit Torque Through Stray Field Engineering

Abstract

We proposed a novel multilayer structure to realize the deterministic switching of perpendicularly magnetized layers by spin orbital torque from the spin Hall effect through stray field engineering. In our design, a pinned magnetic layer is introduced under the heavy metal separated by an insulator, generating an in-plane stray field in the perpendicularly magnetized layer. We have confirmed the deterministic switching of perpendicularly magnetized layers by studying the switching loops and dynamic switching processes through micromagnetic simulation. The in-plane stray field accounts for the deterministic switching exhibited in the structure, and the ultimate reversal state of the magnetic layer is predictable when the applied spin current density is above the critical spin current density. Moreover, the stray field is easily adjusted in a broad range by varying the saturation magnetization and dimensions of the pinned layer to accommodate different perpendicularly magnetized materials without any external magnetic field.