Angle and rotational direction dependent horizontal loop shift in epitaxial Co/CoO bilayers on MgO(100)

Co/CoO belongs to the typical exchange bias systems which have been investigated for decades. Surprisingly, Co/CoO thin film systems epitaxially grown on MgO(100) substrates show a strong influence of the relative orientation of the average uncompensated antiferromagnetic magnetization with respect to the cooling field direction, giving rise to unexpected asymmetric angular dependencies of the horizontal loop shift as well as the sign of the transverse magnetization peaks in magneto-optical Kerr effect (MOKE) experiments. In this paper, we provide a broad overview of the influence of cooling field orientation and sample orientation on magnetization reversal processes in this system.