Properties of ferroelectric SrBi2Ta2O9-Bi4Ti3O12 thin films derived by the sol-gel method

Ferroelectric (1−x)SrBi2Ta2O9-xBi4Ti3O12(x=0-0.4) thin films were fabricated by the sol-gel method. Multiple phases of SrBi2Ta2O9-Bi3TiTaO9 solid solution, SrBi2Ta2O9 and Bi4Ti3O12 were formed and good electric properties were obtained in the films. With the increase in composition, x, the remnant polarization has no obvious change, but the coercive field increased. The 0.8SBT-0.2BIT films showed the lowest dielectric constant values, well-saturated hysteresis loops and lower leakage current densities. The parameters of the 0.8SBT-0.2BIT film annealed at 750 °C were 150 for dielectric constant, 13.5 μC/cm2 for remanent polarization (2Pr), 152 kV/cm for coercive field (2Ec) and 5.88×10−8 A/cm2 (at 200 kV/cm) for leakage current density.