Field-free spin-orbit torque-induced perpendicular magnetization switching in YIG/Ta/CoTb/Pt

Spin-orbit torques (SOTs) provide a physical basis for designing new spintronic memory and logic devices. The key to the application is the realization of field-free SOT-driven magnetization switching. In this study, Ta/CoTb/Pt ferromagnetic multilayers were grown on yttrium iron garnet (YIG) magnetic insulating film. We achieved current-induced CoTb magnetization switching under zero magnetic field by using the magnetic dipole interaction field generated by the YIG magnetic insulating layer applied to the CoTb film with perpendicular magnetic anisotropy and the spin torque generated from Ta and Pt spin source layers. Experimentally, we measured the magnetization reversal behavior induced by pulse current through anomalous Hall effect and anomalous Hall resistance and observed the magnetic domain wall motion characteristics driven by pulse current under the magneto-optical Kerr microscope. Moreover, due to the influence of the magneto-optical Kerr microscope, it was found that for YIG/Ta/CoTb/Pt devices, the magnetic domain of ferromagnetic CoTb moves and completes magnetization switching by forming stripe-like features, which is significantly different from the magnetization switching characteristics of the Si/Ta/CoTb/Pt film. Our results may provide a new degree of freedom for the potential application value of the research of spintronic low-power devices, particularly field-free SOT-driven switching-based devices.