Microstructure and electrical properties of Ba0.7Sr0.3(Ti1-xZrx)O3 thin films prepared on copper foils with sol-gel method

Ba0.7Sr0.3(Ti1-xZrx)O3 (x = 0, 0.1, 0.2) (BSZT) thin films have been prepared on copper foils using sol-gel method. The films were annealed in an atmosphere with low oxygen pressure so that the substrate oxidation was avoided and the formation of the perovskite phase was allowed. The X-ray diffraction results show a stable polycrystalline perovskite phase, with the diffraction peaks of the BSZT films shifting toward the smaller 2θ with increasing Zr content. Scanning electron microscopy images show that the grain size of the BSZT thin films decreases with increasing Zr content. High resolution transmission electron microscopy shows the clear lattice and domain structure in the film. The dielectric peaks of the BSZT thin films broaden with increasing Zr content. Leakage current density of Ba0.7Sr0.3(Ti1-xZrx)O3 (x = 0.1) thin film is the lowest over the whole applied voltage.