Effect of Zr/Ti ratio on the microstructure and ferroelectric properties of lead zirconate titanate thin films

Lead zirconate titanate (PZT) thin films with Zr/Ti ratios of 30/70, 40/60, 52/48, 60/40, and 70/30 derived from metal alkoxide precursor solution were deposited on platinized silicon substrates by sol–gel technique. X-ray diffraction analysis showed that the films exhibit a single perovskite phase with mostly (1 1 1) preferred orientation. The SEM study proved that PZT films possess a dense microstructure without cracks and voids. Ferroelectric and dielectric phenomena were studied in correlation with the variation of Zr/Ti ratio and its influence on crystallographic structure and morphology of the films. It was found that, among all the investigated films, the PZT films with Zr/Ti ratio of 52/48 exhibit the most promising properties including high remanent polarization and low coercive field of ≈24 μC cm−2 and 72 kV cm−1, respectively. The films were also characterized by excellent dielectric properties (dielectric permittivity ≈1200 and loss factor ≈0.02).