Dielectric Characteristics in BiFeO₃-Modified SrTiO₃ Incipient Ferroelectric Ceramics

We investigate the dielectric and ferroelectric properties of Sr_1?xBi_xTi_1?xFe_xO₃ solid solutions (x=0, 0.05, 0.1, 0.15 and 0.2) together with their structures. Through the analysis of Rietveld refinement of powder x-ray diffraction, a cubic structure in space group Pm3m is determined for all the compositions. An obvious dielectric relaxation peak differing from SrTiO₃ is observed in the present ceramics. The peak temperature T_m increases with increasing x, and it approaches room temperature at x=0.2. The Vogel–Fulcher law and Curie–Weiss law fittings further confirm the relaxor ferroelectricity in the present ceramics.