γFe2O3films with uniaxial anisotropy obtained by a new assisted CVD technic

Pyrolysis of an ultrasonic generated aerosol has been used for growing thin oxides films (2000 to 8000 Å), in the system γFe2O3- Fe3O4. Polycrystalline films with good adherence and homogeneity were obtained on glass substrates. The cubic lattice parameter was observed to be sensitive to impurities and to the film-substrate strain interaction. The oxidation state of iron was discussed in regard to the experimental growing conditions and the corresponding magnetic properties were investigated. Partially oxidized Fe3O4films and pure γ Fe2O3films both with a magnetization of 400 emu/cc and a coercivity of 400 Oe have been obtained. Controling the oxidation degree of the spinel phase by a post deposition heat treatment allowed us to prepare films with a coercivity ranging from 400 to 1000 Oe. Values as high as 2000 Oe were even obtained by doping the thin films with a few percent of cobalt.