Dielectric Properties and Switching Processes of Barium Titanate⁻Barium Zirconate Ferroelectric Superlattices

This article is devoted to the investigation of the dielectric and repolarization properties of barium zirconate and barium titanate BaZrO₃/BaTiO₃ superlattices with a period of 13.322 nm on a monocrystal magnesium oxide (MgO) substrate. Synthesized superlattices demonstrated a ferroelectric phase transition at a temperature of approximately 393 °C, which is far higher than the Curie temperature of BaTiO₃ thin films and bulk samples. The dielectric permittivity of the superlattice reached more than 10⁴ at maximum. As the electric field frequency increased, the dielectric constant of the studied superlattice decreased over the entire study temperature range, but position of the maximum dielectric constant remained the same with changing frequency. The temperature dependence of the inverse dielectric permittivity 1/ε(T) for the studied samples shows that, in the investigated superlattice, both Curie⁻Weiss law and the law of "two" were followed. Additionally, the ε(T) dependences showed practically no temperature hysteresis with heating and cooling. Samples of synthesized superlattices had a relatively small internal bias field, which was directed from the superlattice towards the substrate.