Phase States and Dielectric Properties of Li_(0.17)Na_(0.83)Nb_yTa_(1-y)O_3 Ceramic Solid Solutions Prepared by High-Pressure, High-Temperature Synthesis

摘要

The electrical properties and phase states of Li0.17Na0.83Nb??a(1 -?)O(3) (y = 0.1-0.5) ferroelectric perovskite solid solutions prepared by high-pressure, high-temperature synthesis have been studied using impedance spectroscopy. The epsilon'(T) and sigma(sv)(T) curves of the solid solutions have been shown to have anomalies due to phase transitions of the materials. Their Curie temperature has been found to decrease with increasing Ta concentration. The static electrical conductivity of the solid solutions has been measured as a function of temperature and the enthalpies of activation of charge carriers in them have been evaluated. The Li0.17Na0.83Nb0.1?a(0.9)O(3) solid solution has been shown to be a high-temperature superionic conductor. Possible mechanisms of the observed phenomena are discussed.