Temperature dependence of ferroelectric and magnetic properties in polycrystalline BiFeO3 films

A BiFeO₃ film was fabricated by a chemical solution deposition (CSD) method onto the Pt/Ti/SiO₂/Si(100) substrate followed by a post-deposition annealing at 973 K for 10 min in air. An X-ray diffraction measurement indicates the formation of the polycrystalline single phase of the BiFeO₃ film. The high remanent polarization of 89 muC/cm² was observed at 90 K together with the relatively low electric coercive field of 380 kV/cm, though the ferroelectric hysteresis loops could not be observed at room temperature due to the high leakage current density. Magnetic measurements indicate that the low remanence magnetization of around 2 emu/cm³ and the magnetic coercivity field of around 0.5 kOe were obtained at room temperature. These magnetic parameters increased around twice the value by decreasing the temperature to 100 K.