Domain structure in a micron-sized PbZr1−xTixO3 single crystal on a Ti substrate fabricated by hydrothermal synthesis

Hydrothermal synthesis is an attractive method for the deposition of ferroelectric thin films because it can realize a low processing temperature of 200 °C or less. In this study, micron-sized PbZr1−xTixO3 (PZT) single crystals and thin films were fabricated on a Ti substrate at 160 °C by hydrothermal synthesis. The ferroelectricity of the crystals was investigated using local piezoresponse hysteresis, while their domain structure was investigated using high-resolution transmission electron microscopy (HRTEM) measurement. The isolated PZT single crystal exhibited hysteresis behavior of the piezoresponse, which represents ferroelectricity. From the HRTEM observations of a crystallite in polycrystalline PZT thin film, we found a twinned domain structure in the form of a … c/a/c/a … polydomain pattern. On the basis of the HRTEM observations, we proposed a three-dimensional domain structure for the isolated PZT single crystal; the c/a domain walls form along coherent {101} planes in the tetragonal cell. This structure was experimentally verified by scanning nonlinear dielectric microscopy.