Structure and magnetic properties of epitaxial ferrite film grown on MgO(001) by MBE

Single-crystal epitaxial thin films of spinel have been grown on MgO (001) with a MgO buffer layer by molecular beam epitaxy, using magnetite as a source for electron beam evaporator at a temperature of 273-523 K. The structure and magnetic properties of the films have been characterized by a variety of techniques, X-ray diffraction, Auger electron spectroscopy, transmission electron microscopy, and vibrating sample magnetometry. It is shown that the structure of the layer grown at 423 K is spinel, close to gamma-Fe2O3 with a lattice constant of 0.837 nm. The interface between MgO buffer layer and spinel layer is not flat because of interdiffusion of Mg, however, Mg is not detected in the films except for the vicinity of the interface. The spinel layers are considered to be slightly strained. The film exhibits a very low coercive field of 63 Oe, which can be explained by the reduction in strains, (C) 2004 Elsevier B.V. All rights reserved.