High-temperature impedance spectroscopy of BaFe0.5Nb0.5O3 ceramics doped with Bi0.5Na0.5TiO3

Bi0.5Na0.5TiO3 (BNT)-doped BaFe0.5Nb0.5O3 (BFN) ceramics were synthesized by a two-step solid-state reaction. Temperature dependence of dielectric properties measured at different frequencies was investigated over broad temperature and frequency ranges. Impedance spectroscopy and universal dielectric response were employed to study the relaxation behavior and conductivity mechanism of the ceramics in a frequency range from 40 Hz to 100 MHz and a temperature range from 300 K to 800 K. The complex plane impedance data revealed the bulk and grain boundary contributions toward conductivity processes in the form of semicircular arcs. The high-temperature conductivity of ceramics is attributable to thermally activated second ionized oxygen vacancy.