EFFECT OF BARIUM ON DIELECTRIC, FERROELECTRIC, IMPEDANCE AND ELECTRICAL MODULUS PROPERTIES OF Bi0.5Na0.5TiO3 CERAMICS

Abstract

Perovskite structured ferroelectric ( Na 1/2 Bi 1/2)0.945 Ba 0.055 TiO 3 (BNBT-5.5) material has been synthesized by the conventional sintering technique. X-ray analysis on the material showed a single phase compound with rhombohedral structure with lattice parameters a = 3.89 Åand α = 89.893 Å. Frequency and temperature dependence of dielectric permittivity, impedance, modulus and conductivity have been performed in the frequency and temperature range 45 Hz–5 MHz and 35–595°C, respectively. The observed low frequency dielectric dispersion (LFDD) in the material could be explained by Jonschers power law and evaluated activation energies at different temperature regions. Impedance spectroscopy study showed the presence of both bulk and grain boundary effects in the materials. The ac conductivity spectrum obeyed the Jonscher's power law. Modulus analysis indicated the possibility of hopping mechanism for electrical process in the system.