Direct fabrication of ferrite MFe2O4 (M = Zn, Mg)/Fe composite thin films by soft solution processing

Spinel ferrite/metal composite thin films of MFe2O4/Fe (M = Zn, Mg) with controlled grain sizes and shape were directly fabricated by a soft solution-processing route that involved the liquid-solid interfacial hydrothermal reaction of an Fe substrate with metal ions M2+ (M = Zn, Mg) in ammonia solution at lower temperatures (<200 C). The grain particles of ZnFe2O4/Fe composite thin films show a well-developed octahedral shape with highly {111} preferential orientation, whereas the grain particles of MgFe2O4/Fe thin films displayed spherical shape. The saturation magnetization of the ferrite/Fe composites thin films was found to be much improved compared with that of single-phase ferrite products, and the ferrite/Fe thin films displayed superparamagnetism. The present soft-solution processing route will be extended to fabricate other novel ceramic/metal composite thin films.