Prominent ferroelectricity of BiFeO3 thin films prepared by pulsed-laser deposition

Ferroelectric BiFeO3 thin films have been prepared on Pt/TiO2/SiO2/Si substrates in various oxygen pressures of 0.001–0.1 Torr at a temperature as low as 450 °C by pulsed-laser deposition. The crystallinity of the films was studied by x-ray diffraction. X-ray photoelectron spectroscopy showed that the films have a single phase of perovskite BiFeO3. The BiFeO3 thin films deposited at 0.01–0.1 Torr show good current-density–applied-voltage characteristics. It is obtained from polarization–electric-field characterization that 2Pr is about 71.3 μC/cm2 and 2Ec is 125 kV/cm. Stable current density and saturated ferroelectric hysteresis loop have been observed in BiFeO3 thin films.