Strontium barium bismuth tantalate layered perovskites: thin film preparation and ferroelectric characteristics

The preparation processes and ferroelectric characteristics of barium cation-incorporated SrBi2Ta2O9 thin films have been investigated in this study. Complete solid solutions of (Sr1−xBax)Bi2Ta2O9 thin films are formed on Pt/Ti/SiO2/Si substrates using a metalorganic decomposition method after annealing at 700°C. The lattice constant along the c-axis of formed solid solutions monotonously increases with increasing the contents of barium cations. The microstructure and surface morphologies of films significantly vary with the composition. The grain size and the roughness of (Sr1−xBax)Bi2Ta2O9 films increases as the contents of barium cations increase. All prepared films exhibit ferroelectric characteristics. Increasing the annealing temperature is found to significantly enhance the remanent polarization of prepared thin films. In the formed solid solutions, (Sr0.5Ba0.5)Bi2Ta2O9 thin films exhibit the highest remanent polarization. This is attributed to large grain size and preferred a-axis orientation of formed films.