The Hysteretic Behavior of Angular Dependence of Exchange Bias in NiFe/granular-FeMn-MgO Bilayers

We investigate the hysteretic behavior of the angular dependence of exchange bias for a series of polycrystalline NiFe/(FeMn)_1?x(MgO)_x bilayers with varying x. For x=0.025, the antiferromagnetic layer is of the largest degree of the fcc (111) preferred texture. At the same x, both the exchange field and blocking temperature acquire maximal values. In particular, the hysteretic behavior of the angular dependence between clockwise and counter-clockwise rotations shows minimal angular shift. These results can be explained in terms of the thermal activation model.