Controlling magnetic vortices through exchange bias

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The magnetization reversal in Permalloy (Py) and Py-IrMn disks (1μm diameter) is investigated. The Py disks reverse their magnetization via vortex state formation. Conversely, if the Py-IrMn disks are field cooled from above the blocking temperatureTB, a critical angle with respect to the cooling direction is set, beyond which the vortex no longer nucleates. This angle can be experimentally tuned by varying the magnitude of the exchange bias field. Furthermore, the coupling with IrMn can also induce an enhancement of the vortex stability when the disks are zero-field cooled from above TB.