Epitaxial and polycrystalline BaFe12O19 thin films grown by chemical vapour deposition

Epitaxial and polycrystalline barium hexaferrite BaFe₁₂O₁₉ thin films were prepared by metalorganic chemical vapour deposition (MOCVD). Films were grown by a liquid MOCVD technique which aim is to control precisely the precursor vapour pressures. Two kinds of substrates were used: sapphire (001) and silicon thermally oxidized. On Si/SiO₂ films are polycrystalline and the magnetization is isotropic. On Al₂O₃ (001), structural studies reveal the films to be predominantly single phase, well crystallized without annealing procedure and with the c-axis perpendicular to the film plane; epitaxial relationships between the film and the substrate were determined. The magnetic parameters, deduced from vibrating sample magnetometer measurements, show a high dependence of the magnetization with the orientation of the field with respect to the surface of the film.