Epitaxial PbTiO₃ thin films on SrTiO₃(100) and SrRuO₃/SrTiO₃(100) substrates deposited by a hydrothermal method

Lead titanate (PbTiO₃) thin film is a promising material for ultrahigh-density ferroelectric data storage systems, pyroelectric sensors and ferroelectric optical devices. In this study, high-quality epitaxial PbTiO ₃ thin films were deposited on SrTiO₃(100) and SrRuO ₃/SrTiO₃(100) by a hydrothermal method. The crystal orientation of the deposited film was investigated with a high-resolution X-ray diffraction mapping system. The full width at half maximum (FWHM) of the rocking curve of the (002) PbTiO₃ film on SrTiO₃ was 0.060°. The reciprocal space mappings of (103) verified that the PbTiO ₃ films had perfect c-axis orientation. The self-aligned polarizaton was confirmed with observation using a scanning nonlinear dielectric microscope. The PbTiO₃ on SrRuCO₃/SrTiO₃(100) was used for the D-E hysteresis curve measurement and the remanent polarization was 96.5μC/cm². Domain patterning was applied to a 50-nm-thick PbTiO₃ film using a conductive cantilever probe. The minimum radius of the nano domain dot was 12nm, corresponding to a data density of 1 Tbit/inch².