Controlling vertical magnetization shift by spin-orbit torque in ferromagnetic/antiferromagnetic/ferromagnetic heterostructure

Abstract

We report the control of the vertical magnetization shift (VMS) and exchange bias through spin-orbit torque (SOT) in Pt/Co/Ir25Mn75/Co heterostructure devices. The exchange bias accompanying with a large relative VMS of about 30% is observed after applying a single pulse of 40 mA in a perpendicular field of 2 kOe. Furthermore, the field-free SOT-induced variations of VMS and exchange bias are also observed, which would be related to the effective built-in out-of-plane field due to unequal upward and downward interfacial spin populations. The SOT-induced switched fraction of out-of-plane interfacial spins shows a linear dependence on relative VMS, indicating that the number of uncompensated pinned spins is proportional to the switched interfacial spins. Our finding offers a comprehensive understanding for electrically manipulating interfacial spins of antiferromagnetic materials.