Enhanced Ferromagnetic, Ferroelectric, and Dielectric Properties in BiFeO3-SrTiO3-Bi0.5Na0.5TiO3 Ceramics

Room-temperature multiferroic (1 - x)BiFeO3-x(SrTiO3-Bi0.5Na0.5TiO3) (BFO-ST-BNT) (x = 0 to 0.5) solid solutions have been prepared by the modified Pechini method, and their structural, ferromagnetic, ferroelectric, and dielectric properties systematically studied. In addition, a gradual phase transformation from rhombohedral to pseudocubic structure was observed between the compositions with x = 0.2 and x = 0.3. Compared with pure BiFeO3, significantly enhanced remanent magnetization (M (r) = 0.11 emu/g) was determined in the sample with x = 0.2 at room temperature. Although the ferroelectric properties exhibited overall enhancement with increasing x, relatively large remanent polarization P (r) (1.14 mu C/cm(2) at 300 K) was achieved simultaneously at the optimal composition with x = 0.2. Moreover, we measured an outstanding relative dielectric constant of over 16,700 at frequency of 10 kHz for the sample with x = 0.2, which is attributed to polarization of defect dipoles. This comprehensive enhancement of the ferromagnetic, ferroelectric, and dielectric properties indicates that BFO-ST-BNT ceramics are promising candidates for use in multiferroic applications.