Exploration of magnetization reversal and coercivity of epitaxial NiO {111}/NiFe films

We have grown epitaxial NiO {111} films of thicknesses ranging from 60 to 1200 Å, deposited 45 Å NiFe films on these NiO substrates, and made measurements of exchange field and coercivity, of the effective uniaxial anisotropy, of rotational hysteresis, and of the training effect on these films. We find that the large coercive fields, ∼500 Oe, observed in these epitaxial systems can be understood using a model in which the magnetization reversal process is by rotation, with the coercive field determined by the effective uniaxial anisotropy of the system. This effective anisotropy is in turn determined by the anisotropy of the NiO and depends on NiO thickness.