Ferroelectric Phase Transitions of Modified [(Na0.5Bi0.5)1 –xLax]TiO3 (x = 0–0.1) Sodium Bismuth Titanate-Based Ceramics

We have studied the effect of A-site cation substitutions in sodium bismuth titanate on the structural parameters, microstructure, and dielectric and ferroelectric properties of [(Na0.5Bi0.5)1 –xAx]TiO3 (A = La3+, x = 0–0.1) ceramics, including those modified with KCl additions. The samples have been shown to undergo phase transitions, which show up as anomalies in dielectric permittivity near ~400 K and peaks at ~600 K. The phase transitions near 400 K exhibit well-defined relaxor behavior, indicative of the presence of polar regions in a nonpolar matrix, as supported by laser second harmonic generation measurements.