Coercivity enhancement in exchange biased systems driven by interfacial magnetic frustration

We report the temperature and cooling field dependence of the coercivity of exchange biased MnF2/Fe bilayers. When the antiferromagnetic surface is in a stare of maximum magnetic frustration and the net exchange bias is zero, pre observe a strong enhancement of the coercivity, which is proportional to the exchange coupling between the layers. Hence, the coercivity can be t uned in a reproducible and repeatable fashion in the same sample. We propos e that a frustrated interface provides local energy minima which effectivel y pin the propagating domain walls in the ferromagnet, leading to an enhanc ed coercivity.