Phase Transitions and the Condition of Near-Interface Layer in PbZrO<sub>3</sub> Epitaxial Films on SrRuO<sub>3</sub>/SrTiO<sub>3</sub> Substrate

Abstract

We have studied temperature-induced phase transitions in PbZrO3 thin films by X-ray diffraction. By tracing the temperature dependence of superstructure reflections we show that the onset of antiferroelectric ordering takes place highly continuously on cooling and another, presumably ferroelectric phase is present at high temperatures, between the antiferroelectric and cubic phases. To clarify the possible reason for this behavior, we have investigated the X-ray diffraction profile with momentum transfer along the normal to the film surface and carried out the relevant simulation using the formalism of scattering by inhomogeneously deformed sample. From the analysis it follows that the near-interface layer is effectively compressed along the normal to the film. We associate this observation with the presence of dislocations through which the film is relaxed. The results suggest that the reasons for the phase transition sequence modification in thin films can be associated with inhomogeneous distribution of stress and defects in the near-interface area.