Preparation and magnetic properties of CoFe2O4/TiO2 composite films

Using (Ti(OC₄H₉)₄) and metal chlorates as starting materials, CoFe₂O₄/TiO₂ composite films were prepared by sol-gel method. The effects of heat treatment temperature and pH of the precursor on microstructure and magnetic properties were studied. The phase structure of the samples was examined by X-ray diffraction. The microstructure was examined by scanning electron microscope, atomic force microscope and polarized microscope. The magnetic property was measured by vibrating sample magnetometer. The results show that the crystals of different phases grow up independently. CoFe₂O₄ is uniformly embedded into the TiO₂ matrix in the prepared composite films, and the growth of composite films is dependent on the heat treatment temperatures and PH of the precursor. The average size of CoFe₂O₄ crystal is 19 nm in Nanocomposite film prepared when the heat treatment temperature is 800°C and the pH of the precursor is between 2 and 3. The magnetism of the composite films is enhanced as the heat treatment temperature increases. Supported by the National Natural Science Foundation of China (Grant Nos. 50632030 and 10474077), and the Natural Science Foundation of Shaanxi Province (Grant No. 2006E₁35)