Constrained ferroelectricity in the (001)-textured superlattices of PbZrO3∕BaZrO3

A constrained ferroelectricity is found in the (001)-textured PbZrO3∕BaZrO3 superlattice films having an average composition of (Pb0.75Ba0.25)ZrO3, which is characterized by the linear dependence of remanent polarization (Pr) and coercive field (Ec) on the applied voltage and its stability against temperature change up to 100°C. A model based on equilibrium of electrostatic energy in dielectric stressing of the superlattice and polarization switching in the ferroelectric sublayer is proposed. The dielectric constant evaluated from a fitting of the measured Pr and Ec relations to the model is consistent to that obtained from impedance measurement. The thermal stability of this “linear” ferroelectricity can be also explained by the temperature-insensitive permittivity of the superlattice films, according to the proposed model.