Asymmetric magnetization reversal in a single exchange-biased micro bar

Abstract

The asymmetric magnetization reversal is studied in a single exchange-biased microbar of 1.5×13μm2 with anisotropic magnetoresistance and magnetic force microscopy. The asymmetric hysteresis loop of CoFe∕CrMnPt shows a repeatable rotation process, followed by an irreversible nucleation process that is marked by jumps in the magnetoresistance. The induced unidirectional anisotropy enhances the rotation process in one branch of the hysteresis loop, followed by a sped up nucleation process. Imprinted ferromagnetic domain patterns left behind by the antiferromagnet are observed after the nucleation process occurred but before complete saturation is reached.