Preparation of single-crystal ferrite films

Single-crystal films of spinel ferrites have been deposited epitaxially on MgO substrates from a molten-salt solution by vaporizing the solvent. The ferrite constituents (oxides or carbonates) and anhydrous sodium carbonate are melted on a (100) cleavage surface of a MgO single crystal. The melt wets the MgO so that it spreads over the surface as a uniform, thin, liquid layer. The solution is maintained at 1100°-1250°C for 5-20 h in order to vaporize the solvent, thus depositing the ferrite. Crystals 5-50 μ thick and 1 cm 2 area of NiFe2O4, Ni0.5Zn 0.5Fe2O4, CoFe2O4, and Li0.5Fe2.5O4 (the latter using Li 2CO3 as the molten-salt solvent) have been grown by this method. The ferrite films grow with the same orientation as the substrate. © 1967 The American Institute of Physics.