Impedance spectroscopy of bismuth sodium titanate: Barium titanate ceramics with manganese doping

Abstract

In this work we use Impedance Spectroscopy (IS) to study lead-free ceramics of perovskite structure (Bi1/2Na1/2TiO3)0.925(BaTiO3)0.075 with Mn doping of 0, 0.2, 1.0, and 2.0 at.%. We compare our IS results with permittivity results, using dielectric to resistivity transformation equations which allow us to display results either as permittivity or as resistivity. We observe ionic conductivity dominating at lower temperatures, giving way to electronic conductivity at higher temperatures. The permittivity shows deviations from Curie-Weiss behavior characteristic of relaxor ferroelectrics. The 0.2% Mn samples show the highest ionic resistivity, which will reduce heating for high voltage piezoelectric applications. They also have the highest Curie-Weiss temperature and Burns temperature.