Ferroelectric transitions in epitaxial Pb0.5Sr0.5TiO3films studied by dielectric analysis

Abstract

The intrinsic ferroelectric phase transitions occurring in perovskite-structure epitaxial films of Pb${}_{0.5}$Sr${}_{0.5}$TiO${}_{3}$ are experimentally assessed and studied. The low-frequency dielectric response of thin-film heterostructure capacitors, polycrystalline films, and prototype ceramics is analyzed using phenomenological and equivalent circuit approaches. To explore the paraelectric to ferroelectric phase transitions, the derivative of inverse permittivity is used. In ceramics, the transition is of first order. In the epitaxial films, the order of the intrinsic transitions is difficult to determine in terms of classical phenomenology. Based on analysis of such factors as epitaxial strain, internal electric field, and domain configurations, we suggest that the configuration and dynamics of ferroelectric domains are responsible for this. The origin of apparently relaxor-looking dielectric peaks is discussed.