Analysis of Bending Displacement of Lead Zirconate Titanate Thin Film Synthesized by Hydrothermal Method

Lead zirconate titanate solid-solution (PZT) films with various thicknesses were synthesized on titanium substrates by repeated hydrothermal treatments. Young's modulus and the density of the PZT film were measured by the vibrating-reed technique and Archimedes' method, respectively, and they were lower than those of PZT ceramic. We fabricated bimorph-type bending actuators using those films and analyzed the displacement induced by the electric field. It was found that the piezoelectric constant and electromechanical coupling factor of the PZT film were comparable to those of the ceramic, and also that the displacement was caused by the piezoelectric effect. The actuators were bent by applied voltage without poling, because the polar axes in the as-deposited film were aligned in the direction from the film surface to the substrate.