Current switching of interface antiferromagnet in ferromagnet/antiferromagnet heterostructure

Recently, electrical switching of interface states in nonferromagnet/ferromagnet (FM)/antiferromagnet (AFM) heterostructure using spin–orbit torque (SOT) is promising due to its high efficiency, zero magnetic field, and multilevel memory state. However, the reversal mechanism of the AFM interface state is still unclear. In this work, we explained the bipolar current switching of the AFM interface state at zero magnetic field by spin–orbit torque (SOT) in a perpendicularly magnetized Pt/Co/IrMn multilayer. By considering symmetry, we reveal that the mechanism behind the AFM interface bipolar current switching is consistent with FM layers perpendicularly switching induced by SOT. The distinct AFM bipolar current switching by SOT is contributed to the symmetry broken by adjacent FM interface coupling. Under such broken symmetry, the antiparallel interface configuration (AP) between FM and AFM could be switched to parallel configuration (P) for both positive and negative currents; however, P is only allowed to be switched to the AFM multiple domain configuration (M), instead of AP. Our result will be helpful for the formulation of a comprehensive understanding of AFM switching induced by SOT and for the development of the interface AFM spintronic devices.