The formation and structural characterization of highly (111)-oriented Co3O4 and CoFe2O4 films prepared by a novel procedure from 001-oriented NaCoO2 and Na(CoFe)O-2 is reported. The Na(CoFe)O-2 films were deposited on MgO, SrTiO3, LaAlO3, and Zr(Y)O-2 single crystals with (100) and (111) orientations by chemical solution deposition method and crystallized at 700 degrees C.
Subsequently they were transformed into (111)-oriented spinel phase during post-growth annealing at 800-1000 degrees C. Morphology and structure of the films was investigated by means of scanning electron microscopy and X-ray diffraction.
While all spinel films exhibit pronounced out-of-plane orientation irrespective of substrate, the rate of in-plane orientation strongly depend on lattice misfit values. Different epitaxial phenomena ranging from true one-to-one epitaxy to the existence of many-to-one epitaxy involving two or more orientations were determined by full 3D texture analysis.