Magnetization switching through spin-Hall-effect-induced chiral domain wall propagation

The influence of spin-Hall-effect spin torque (SHE-ST) induced by in-plane charge current was studied in microscale Ta/Co20Fe60B20/TaOx films with perpendicular magnetization. Simultaneous electrical transport and polar magneto-optical Kerr effect (MOKE) imaging experiments were used to investigate the switching dynamics. A rich set of switching behaviors was observed, which can be well understood by analyzing a switching-phase diagram and polar MOKE images, considering the competition between SHE-ST and the externally applied magnetic field. Furthermore, we found that domain walls with a particular chirality were dominant in our devices, which suggests the presence of the Dzyaloshinskii-Moriya interaction in the present material system.