Manipulating exchange bias in Ir25Mn75/CoTb bilayer through spin–orbit torque
Ruobai Liu, Yiyang Zhang, Yuan Yuan, Yu Lu, Tianyu Liu, Jiarui Chen, Lujun Wei, Di Wu, Biao You, Wei Zhang, Jun Du
Abstract
Manipulation of exchange bias (EB) via spin-current-induced spin–orbit torque (SOT) is of great importance in developing full electric control spintronic devices. Here, we report on SOT-dominant manipulation of the interfacial antiferromagnetic spins and the related perpendicular EB (PEB) in the IrMn/Co1-xTbx (CoTb) bilayers with various Tb contents. No matter the magnetization of the ferrimagnetic CoTb layer is Co-dominant or Tb-dominant; all the samples were perpendicularly magnetized, and spontaneous PEB could be established during the isothermal crystallization of the IrMn layer. The SOT-induced EB switching could be accomplished with assistance of an in-plane or out-of-plane external magnetic field, associated with a monotonic reduction of the EB switching fraction by increasing x. This phenomenon is attributed to weakening of the interfacial exchange coupling between the CoTb and IrMn layers as x is increased. These findings provide a way to design high energy-efficient spintronic devices by employing the antiferromagnet/ferrimagnet bilayers, which may have weak stray field and strong robustness in contrast to commonly used heavy-metal/ferromagnet/antiferromagnet trilayers.