Impedance Spectroscopy Analysis of (1-<i>x</i>)Ba_0.06(Na_1/2Bi_1/2)_0.94TiO₃-<i>x</i>NaTaO₃ Ceramics

Abstract

The conventional solid-state reaction method was used to prepare the lead-free solid-solution (1-x)Ba0.06(Na0.5Bi0.5)0.94TiO3-xNaTaO3; 0 ≤ x ≤ 1. X-ray diffraction analysis of all the compositions of the series confirmed the solid solution’s successful formation. The electrical impedance and conductivity of the material were studied using the impedance spectroscopy method at temperatures ranging from room temperature to 500○C. For the Ba0.06(Na0.5Bi0.5)0.94TiO3 rich compositions ac conductivity increased with frequency at all temperatures, whereas for the NaTaO3 rich compositions ac conductivity exhibited a frequency-independent behaviour. As the amount of NaTaO3 incorporated into the compound Ba0.06(Na0.5Bi0.5)0.94TiO3 was increased, a transition occurred in the electrical impedance, specifically, the impedance values shifted from low to high. A theoretical model based on correlated barrier hopping (CBH) has been used to explain the conduction mechanism in these solid solutions.