Epitaxial growth of CoFe2O4 on SrTiO3 (100) and MgO (100) substrates without buffer layer by laser molecular beam epitaxy technique

Among the family of ferrite materials, cobalt ferrite (CoFe2O4) is unique in that it has the highest values of magneto-crystalline anisotropy and magnetostriction. Recently, much of the efforts have been focused on the fabrication of single crystalline cobalt ferrite films. For the epitaxial growth of cobalt ferrite, the issues of lattice parameter and crystal symmetry mismatch with the substrate are of considerable importance. The growth of thin films of CoFe2O4 on MgO and SrTiO3 single crystal substrates is reported in this paper. The key parameters on the growth modes were investigated by changing oxygen pressure and substrate temperature. Results show that the two-dimensional layer-by-layer growth mode only occurs under high oxygen pressure for epitaxy of Co ferrite. The significant observation presents the controllable lattice constant of a highly strained thin film by modulation of the substrate temperature. In this light, to grow high quality Co ferrite thin films on SrTiO3 is of a considerable importance to modulate intrinsic magnetic properties.