Single-Step Synthesis of Ultrafine PLZT from Polymer Gel Precursor: Synthesis, Consolidation, and Dielectric Properties

Abstract

Ultrafine Pb0.93La.07Zr0.60Ti0.40O3 powder was synthesized by autoignition of a metal−polymer gel precursor on a hot plate at very low temperatures without an additional calcination step. The X-ray diffraction result of the as-burnt powder obtained after ignition showed the presence of rhombohedral lead lanthanum zirconate titanate (PLZT) with minute amounts of unreacted PbO. The average particle size calculated from the transmission electron microscopy micrograph of the as-burnt powder was 1.75 nm. The as-burnt ultrafine PLZT powder was sintered directly to 94 and 96% of its theoretical density at 1100 and 1200 °C without any additional calcination. The PLZT sample with 94% theoretical density and grain sizes 0.4−1.0 μm showed a very high dielectric permittivity of ∼5000 and a completely diffused phase transition near the Curie point. This sample exhibited a remnant polarization (Pr) of ∼34.6 μc/cm2. The permittivity of the 1200 °C sintered sample decreases drastically to ∼800. Both of the sintered sampl...