Enhanced ferroelectric properties in Aurivillius PbxBi6−xFe0.5Co0.5Ti4O18 thin films prepared by chemical solution deposition

The Aurivillius compound PbxBi6−xFe0.5Co0.5Ti4O18 thin films were prepared via chemical solution deposition method and the influence of Pb2+ ions doping on the structure, ferroelectric and leakage properties were studied. With the increasing concentration of Pb2+ ions, the lattice distortion is increased and the growth of the films along ab plane is promoted. The calculation results show that the internal stress of the films increases with the increase of Pb2+ concentration. For the samples with low Pb2+ doping concentration (x < 0.6), the leakage current densities are also decreased, which can be attributed to the decrease in oxygen vacancy concentration. Due to the enhanced lattice distortion and decreased leakage current densities, the ferroelectric properties are improved. The film with x = 0.2 has a high saturation polarization of 42.3 µC/cm2. According to the fitting results, the leakage conduction mechanism is attributed to the combined effect of space-charge-limited conduction mechanism and ionic conduction mechanisms.