Phase formation, microstructure and physical properties of lead iron scandium niobate

Lead iron scandium niobate, Pb(Fe1/4Sc1/4Nb1/2)O3 (PFScN), ceramics with pure perovskite phase were produced by conventional solid-state reaction method via a B-site oxide mixing route. Attention is focused on synthesis conditions, where sintering temperature exhibits a pronounced effect on phase formation, density, microstructure and physical properties of the sintered PFScN ceramics. Large bulk density (>95% of the theoretical density) and optimized dielectric properties can be obtained under sintering conditions of 1140–1180 °C for 2 h. Although synthesis conditions have been tailored to optimization, strong frequency dispersion of the dielectric behavior is observed in the sintered PFScN ceramics, which is considered correlating with the possible existence of residual semi-conductive FeNbO4 and/or ScNbO4 compounds and the thermally activated space-charge polarization resulted from the partial reduction of Fe3+ to Fe2+ ions during sintering.