Structure Analysis and Ferroelectric Response of Bi_0.5Na_0.5TiO₃ Nanopowder Synthesized by Sol-Gel Method

In this work, bismuth sodium titanate, Bi_0.5±xNa_0.5±yTiO₃ (BNT, x, y = -0.05-0.08) nanopowders were produced using the low-temperature sol-gel technique. The effects of deficient and excess amounts of Bi and Na on BNT structure were systemically examined through X-ray powder diffraction (XRD), energy dispersive analysis (EDS) and scanning electron microscope (SEM). The optimized composition of the BNT nanopowder was pelletized and sintered at different temperatures (950°C-1150 °C). Highly dense ceramics possessing pure perovskite phase was observed for the sample sintered at an optimum sintering temperature (1100 °C). The ferroelectric properties were found to increase with an increase in sintering temperature up to 1100 °C and then decrease. This study justifies that Bi and Na non-stoichiometry (proper excess), processing and sintering temperatures play important role in the successful synthesis of BNT ceramics.