Structure and Magnetic Property Changes of 2–2-Type BaTiO 3 –CoFe 2 O 4 Composite Thin Films Induced by Magnetic Field Annealing

BaTiO 3 –CoFe 2 O 4 composite thin films with different thicknesses were fabricated via chemical solution deposition. Magnetic annealing and non-field annealing processes were applied in the sintering process, respectively. Variations of the structure and magnetic properties of the composite films induced by the magnetic annealing were investigated. It is found that the mean grain size and grain boundary are increased and decreased, respectively. For the magnetic-annealed films, the internal strain is reduced with the increase of film thickness. Magnetic measurements show that the M s is also increased with the film thickness and the magnetic-annealed films have bigger M s values than the non-field-annealed films. Based on the experimental results, it can be concluded that the effect of magnetic annealing on the structure and properties of the composite films is decreased with the increase of film thickness.