MICROSTRUCTURE OF SOLUTION-PROCESSED LEAD ZIRCONATE TITANATE (PZT) THIN-FILMS

Lead zirconate titanate (PZT) thin films with a composition near the morphotropic phase boundary (Zr/Ti = 53/47) were fabricated by spin deposition of an alkoxide-derived solution and annealed at 650-degrees-C for 30 min. A complex microstructure is observed in which micrometer-scale rosettes of the desired perovskite phase are surrounded by nanocrystalline (10 to 15 nm) grains of pyrochlore structure. Transmission electron microscopy (TEM) demonstrates that the perovskite rosettes-features of approximately circular cross section which grow rapidly within the confined conditions of the thin film-are single crystals despite being highly porous. Pockets of lead-deficient pyrochlore extend throughout the thickness of the film. The only effects of Nb (2%) doping on the microstructure are to increase the fraction of the perovskite phase and the perovskite grain size. Despite the highly irregular shape of the perovskite particles and the presence of some pyrochlore, reasonable ferroelectric properties are measured (spontaneous polarization P(s) almost-equal-to 0.2 C/m2).