Variation of Dielectric and Electrical Properties of Zr-Substituted Lead Calcium Iron Niobate with Temperature and Frequency

The purpose of the present study is to improve the dielectric properties of lead calcium iron niobate with Zr substitution, and to make it suitable for multilayer capacitor applications in resonant circuits. (Pb0.45Ca0.55)(Fe0.5Nb0.5)(1-y) ZryO3 dielectric ceramics where y varies from 0.00 to 0.15 in steps of 0.03, that have been synthesized by the columbite precursor method. Dielectric and electrical properties were measured as a function of frequency (10 kHz to 1 MHz) and temperature. Two frequency dependent anomalies were observed in relative permittivity (epsilon(r)) versus temperature (T) plots around 375 K and between 500 K and 575 K. The temperature coefficient of relative permittivity, (tau(epsilon)) has been improved with the substitution of (Fe0.5Nb0.5)(4+) ions by Zr4+ ions at B-sites. The single semicircle, observed in Nyquist plots at different temperatures, suggests a single relaxation process in the synthesized samples. The activation energies obtained from different dependences are found to be approximately comparable.