Enhanced dielectric property from highly (100)-oriented barium zirconate titanate compositional gradient films

Via the sol–gel process, compositionally graded and homogeneous BaZrxTi1 − xO3 (BZT) thin films were grown on (100)-oriented LaNiO3 (LNO)/Si substrates, respectively. The compositionally graded BZT thin film consisted of BaZr0.05Ti0.95O3 (BZT5), BaZr0.10Ti0.90O3 (BZT10) and BaZr0.15Ti0.85O3 (BZT15). Homogeneous thin films of above three compositions were fabricated for comparison. X-ray diffraction measurements show all the BZT thin films exhibit a single perovskite phase with highly (100)-preferred orientation. The temperature-dependent dielectric properties of these films show typical diffuse phase transition, and the phase transition temperature are all lower than −35 °C. A prominent increase of the dielectric constant and a more aligned surface morphology is observed in the compositionally graded thin film compared to the homogeneous samples.