Microstructures and electrical properties of (1-x) Li0.5Sm0.5TiO3-xNa0.5Bi0.5TiO3 ceramics

A-site (Li0.5Sm0.5)(2+) substitutions for (Na0.5Bi0.5)(2+) of Na0.5Bi0.5TiO3 ceramics were prepared by the conventional solid-state reaction. Structural and electrical properties, including ferroelectric, dielectric, and impedance attributes of the as-prepared ceramics were studied systematically. The new solutions, (1-x) Li0.5Sm0.5TiO3-xNa(0.5)Bi(0.5)TiO(3), could be roughly separated into three groups in accordance with their electrical polarity as microwave dielectric (x < 0.6), relaxor ferroelectric (0.6 <= x <= 0.92), and ferroelectric (x > 0.92). An increase in (Na0.5Bi0.5)(2+) content had a positive impact on the ferroelectric and dielectric properties. Compositions closest to zero temperature coefficient of resonant frequency(tau(f)) were obtained at x = 0.4, where permittivity(epsilon(r)) was 154 and the microwave quality factor, Q x f was 1560 GHz for the samples sintered at 1125 degrees C. The highest discharged energy density of 0.92 J/cm(3) was achieved at x = 0.9. The loss of Bi3+ during sample processing changed the conductive mechanism from electronic conduction to oxide ion conduction, thus presenting a way to optimize the compositions with various donor and acceptor dopants for better performance in microwave and ferroelectric ceramics.