Hysteresis from antiferromagnet domain-wall processes in exchange biased systems

The presence of magnetic impurities in the antiferromagnet can account for some ferromagnetic hysteresis behavior observed in exchange bias systems. We show theoretically that such impurities can modify domain-wall formation in the antiferromagnet, which under certain conditions can give rise to coercivity enhancement and asymmetric hysteresis. The linear dynamics of the ferromagnet/antiferromagnet structure in the presence of impurities is also presented.