Exchange biasing in MBE grown Fe3O4/CoO bilayers: The antiferromagnetic layer thickness dependence

Exchange biasing has been studied for a series of [100] and [111] oriented, epitaxial Fe3O4/CoO bilayers grown by oxidic MBE. The low-temperature exchange biasing versus CoO layer thickness is compared to theoretical models for exchange biasing. We argue that the Malozemoff random field model does not apply to this system. The exchange biasing calculated according to the Meiklejohn-Bean model, assuming nearest-neighbor exchange coupling across a flat and magnetically uncompensated interface, differs for [100] oriented bilayers by a factor of similar or equal to 8 from the experimental value. (C) 1996 American Institute of Physics.