ELECTRO MECHANICAL AND IMPEDANCE STUDIES OF (Na1-xKx)1/2Bi1/2TiO3

Ceramic samples of [(Na1-xKx)(1/2)Bi1/2TiO3] (NKBT) (x = 0.1, 0.15, 0.2, 0.3, 0.45) were prepared by double sintering method. The admittance measurements were carried out in the frequency range of 1 KHz to 10 MHz in the temperature range of 30 degrees C-600 degrees C. The dielectric nature as deduced from admittance data shows a strong temperature and frequency dependence, apart from the relaxor behavior. The admittance data was analyzed by complex plane diagrams i.e., Y' versus Y '' at different temperature. The frequency explicit plots of imaginary component of electric modulus (M '') at various temperatures show peaks shifting to higher frequencies with temperature (> 400 degrees C). The relaxation peaks were effected by the doping. The activation energies are obtained from the data. The electromechanical coefficients K-P, K-31 were calculated from the resonant and anti-resonant frequencies obtained from vector admittance plots. The temperature dependence of electromechanical coefficients is studied. The solid solution samples show higher K-P, K-31 values as compared to pure sodium bismuth titanate.