Preparation and electrical properties of (1−x)(Na0.5Bi0.5)TiO3–xBiAlO3 thin films by a sol–gel process

Lead-free solid solution ceramics (1−x)(Na0.5Bi0.5)TiO3–xBiAlO3(NBT–BA) exhibited an improved ferroelectric and piezoelectric properties compared to the pure NBT ceramics. In this study, (1−x)(Na0.5Bi0.5)TiO3–xBiAlO3 (NBT–BA) (x=0–0.07) thin films were grown on Pt/TiO2/SiO2/Si substrates via a sol–gel process. The compositional dependence and heating treatment temperature dependence of crystalline structure, morphology, and electrical properties of (1−x)NBT–xBA thin films were discussed. We found that the (1−x)NBT–xBA films heated at 700 °C exhibited improved electrical properties compared to the pure NBT thin films. For 0.97NBT–0.03BA film, a larger Pr of 16.5 μC/cm2 and a lower leakage current density of ~10−6 A/cm2 at 200 kV/cm were achieved, and the values of the dielectric constant and dissipation loss at 100 kHz were 385 and 0.029, respectively.