X-ray analysis of epitaxial PbTiO3 thin film grown on an (001) SrTiO3 substrate by metal-organic chemical vapour deposition

Using metal-organic chemical vapour deposition (MOCVD) under reduced pressure at 650 deg. C, stoichiometric PbTiO3 thin films have been epitaxially grown on (001) SrTiO3 single-crystal substrates. A series of x-ray analyses have been carried out to study the microstructures and phase transition process in the as-grown films. X-ray θ-2θ diffraction patterns revealed a pure perovskite phase of the thin film. The epitaxial nature of the film was confirmed by a Laue back-reflection photograph and x-ray Φ scan. From the rocking curve measurement made by the synchrotron radiation method at the Beijing Synchrotron Radiation Facility (BSRF), an a-, c-domain coexisting structure in the 4500 A PbTiO3 thin film had been observed with the c-axis of the c-domain perpendicular to the film surface and the a-axis a-domain tilted away from the surface normal. The phase transition process of the PbTiO3 thin film was investigated through the high-temperature θ-2θ scan patterns; a higher Tc than in the PbTiO3 single crystal had been observed. The strain-driven domain boundary movement in the film was studied by the relative diffraction intensity variation of the (200) and (002) planes. (author)