Magnetic anisotropic properties in Fe3O4 and CoFe2O4 ferrite epitaxy thin films

Epitaxial thin films of Fe3O4 and CoFe2O4 on MgO (001) substrates were grown by molecular beam epitaxy at low temperature growth process. Magnetization and hysteresis loop of both films were measured to investigate magnetic anisotropic properties at various temperatures. Anomalous magnetic properties are found to be correlated with crystalline, shape, and stress anisotropies. The Fe3O4 film below Verwey structural transition has a change in crystal structure, thus causing many anomalous magnetic properties. Crystalline anisotropy and anomalous magnetic properties are affected substantially by Co ions. The saturation magnetization of Co-ferrite film becomes much lower than that of Fe3O4 film, being very different from the bulks. It indicates that the low temperature growth process could not provide enough energy to have the lowest energy state. (C) 2003 Elsevier B.V. All rights reserved.