Interplay between reversal asymmetry, training, and induced anisotropy in epitaxial exchange-biased bilayers

Abstract

Interdiffused $\mathrm{Ni}\mathrm{Mn}∕\mathrm{Ni}$ (111) (antiferromagnet/ferromagnet) bilayers are shown to be a model system for the study of the effects of exchange-induced anisotropy on magnetization reversal asymmetry, training, and exchange bias. Interdiffusion at the interface between antiferromagnet and ferromagnet provides a unique opportunity to assess, in a single sample, the effect of uniaxial vs biaxial anisotropy on phenomena such as training and reversal asymmetry. As predicted by recent theory, we find that the existence of a strong training effect, and an accompanying reversal asymmetry, can be directly correlated with the presence of biaxial exchange-induced anisotropy.