Epitaxial growth of BiFeO3 thin films by LPE and sol–gel methods

Epitaxial BiFeO3 thin films have been grown on the (0 0 1) SrTiO3 and LaAlO3 substrates by liquid phase epitaxy (LPE) and sol–gel methods. The films had an in-plane texture of 2° and out-plane texture of 0.6° and showed a 4-fold symmetry about the c -axis, indicating a distortion of the bulk rhombohedral cell to a tetragonal or cubic structure. The LPE films were both ferroelectric and ferromagnetic. The sol–gel films showed a small linear increase of the magnetisation with the applied magnetic field, indicating they possibly had the same antiferromagnetic behaviour as the bulk crystal. The LPE films exhibited a large leakage current, which probably originated from a relatively high level of Fe2+ in the films induced by the high growth temperature. Fe2+ might also account for the origin of the ferromagnetism in LPE films.