Calculations of exchange bias in thin films with ferromagnetic/antiferromagnetic interfaces

A microscopic explanation of exchange bias in thin films with compensated ferro/antiferromagnetic interfaces is presented. Full micromagnetic calculations show the interfacial exchange coupling to be relatively strong with a perpendicular orientation between the ferro/antiferromagnetic axis directions, similar to the classic ''spin-flop'' state in bulk antiferromagnets. With reasonable parameters the calculations predict bias fields comparable to those observed and provide a possible explanation for both anomalous high field rotational hysteresis and recently discovered ''positive'' exchange bias.