Origin of asymmetric reversal modes in ferromagnetic/antiferromagnetic multilayers

Experimentally an asymmetry of the reversal modes has been found in certain exchange bias systems. From a numerical investigation of the domain state model evidence is gained that this effect depends on the angle between the easy axis of the antiferromagnet and the applied magnetic field. Depending on this angle the ferromagnet reverses either symmetrically, e. g. by a coherent rotation on both sides of the loop, or the reversal is asymmetric with a non uniform reversal mode for the ascending branch, which may even yield a zero perpendicular magnetization.