Magnetic and structural anisotropy of the Co–Fe3O4 films deposited by the thin-liquid film method

Abstract We have deposited Fe 3− x Co x O 4 films on glass substrates from aqueous solutions of CoCl 2 , FeCl 2 and NaNO 2 using the thin-liquid film method. X-ray diffraction patterns of the films show that the relative intensity of (1 1 1) to (3 1 1) reflection increases by the addition of Co 2+ from less than 10% for Fe 3 O 4 ( x =0) to 145% for Fe 2.59 Co 0.41 O 4 . The maximum coercive force ( H c =2110 Oe), which was measured by a vibrating sample magnetometer, is also obtained for the Fe 2.59 Co 0.41 O 4 film. Mossbauer analysis shows that the Co 2+ is located at the octahedral (O h ) site of the inverse spinel and the presence of Co 2+ enhances the perpendicular magnetic anisotropy. The electrical resistivity of the films was changed from about 1 to 10 6  Ω cm by the addition of Co 2+ at room temperature. We suggest that the formation of Co 2+ ion pairs and the excess octahedral stabilization energy of Co 2+ ions in the Fe 3− x Co x O 4 are partly the reasons of the anisotropy.