Synthesis and characterization of PbTiO₃ powders and heteroepitaxial thin films by hydrothermal synthesis

PbTiO₃ powders and heteroepitaxial thin films were produced by the hydrothermal method at 110–200 °C using different bases (Na–, K–, Rb–, Cs–, TMA–, and TBA–OH). Microstructural characterization showed that the tetragonal perovskite films were epitaxial on the SrTiO₃ substrates, with a c-axis out-of-plane orientation. Sequential growth experiments showed that the growth initiates by the formation of 100 nm {100} faceted PbTiO₃ islands followed by coalescence. Small cation bases (Na–, K–, Rb–OH) produced 1.5-μm {100} faceted blocky powders, whereas larger cation bases (Cs–, TMA–, and TBA–OH) formed fewer 500-nm interpenetrating platelets. Nuclear magnetic resonance results showed cation incorporation in the perovskite structure with local disorder on the Pb sites increasing cation size.