Random-field model of exchange anisotropy at rough ferromagnetic-antiferromagnetic interfaces

A field-asymmetric offset of the hysteresis loop in ferromagnetic-antiferromagnetic sandwiches, one of the manifestations of so-called exchange anisotropy, can be predicted from the presence of random interface roughness giving rise to a random field acting on the interface spins. The antiferromagnet breaks up into domains of size determined by the competition of exchange and an additional uniaxial in-plane anisotropy, and this size sets the scale for averaging of the random field.