Using a microscopic Heisenberg model which includes magnetostatic interactions, the Landau-Lifshitz-Gilbert equation of motion is solved in order to study several magnetic properties of ferromagnetic/antiferromagnetic bilayers. For perfectly flat interfaces, it is shown that spin-flop coupling does not lead to exchange bias as has been proposed, but rather gives rise to a uniaxial anisotropy which in turn causes the large coercivities observed in exchange biased films. The introduction of interfacial defects leads to exchange bias of the correct order of magnitude.

• Received 12 June 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.4516