Structure, Microstructure, and Properties of Modified Ceramics (Na,Sr)0.5Bi0.5TiO3

Single-phase ceramic samples of new compositions (Na1 – хSrх)0.5Bi0.5TiO3 (x = 0–0.5), including those modified by additives of SiO2 and ZnO oxides, have been obtained by solid-phase synthesis. The crystal structure and microstructure of these samples, as well as their dielectric, nonlinear optical, and local piezoelectric properties, have been studied. The formation of a perovskite-type phase with a pseudocubic unit cell in all synthesized samples and an increase in the cell volume as a result of partial substitution of perovskite structure cations are established. A decrease in the temperature of ferroelectric phase transitions (confirmed by the methods of dielectric spectroscopy and laser second-harmonic generation) to the tetragonal paraelectric phase is revealed. Remanent piezoelectric hysteresis loops are obtained for the synthesized samples in the polarization switching mode; this result confirms the occurrence of ferroelectric polarization switching.