Effect of Zirconium Substitution on Structural, Dielectric and Electrical Properties of Lead-free Na0.5Bi0.5Ti0.8Zr0.2O3 Ceramics
Abstract
A polycrystalline orthorhombic compound of Zr-doped Na0.5Bi0.5Ti0.8Zr0.2O3 was prepared by conventional solid state reaction method at high temperature(i.e., at 900?C). The effect of Zr (0?2) on the structural and microstructural properties of Na0.5Bi0.5Ti0.8Zr0.2O3 was investigated by XRD and SEM. The electrical properties (dielectric, ferroelectric and impedance spectroscopy) were measured in wide range of frequency and temperature.The room temperature X-ray diffraction study assured the evolution of single-phase compound with orthorhombic structure.The dielectric analysis of Na0.5Bi0.5Ti0.8Zr0.2O3 explored over a broad frequency range ( Hz) at various temperatures (33?C - 500?C) displayed that the dielectric properties of the material are dependent on both frequency and temperature. Dielectric study reveals that the ferro to paraelectric phase transition of the studied compound is a temperature of 268?C. The nature of thevariation of conductivity and value of activation energy in different regions, calculated from the temperature dependence of ac conductivity suggest that the conduction process is of mixed type (i.e. , ionicpolaronic and space charge generated from the oxygen ion vacancies).