Ferroelectric anisotropy in layered compound type of Bi1.75Te0.25Sr0.75Na0.25Nb2O9.

Aurivillius structured ferroelectric ceramics has been prepared with the no minal composition of Bi1.75Te0.25Sr0.75Na0.25Nb2 O-9 (SNBTN0.25). The hot-u niaxial-pressing sintering technique provided highly textured ceramics. Sam ples cutted in two perpendicular directions allows us to study the anisotro pic ferroelectric behaviour of this compound. Two peaks in dielectric const ant versus temperature appear at 375 degrees C and 570 degrees C. The sampl e with a c-axis preferential orientation has lower ferroelectric response t han that one with main cristalographic orientation along the (001) plane, i n which saturated hysteresis loops were obtained. The remanent polarization and the dielectric constant versus temperature measurements suggest that t his material present fluctuations in the composition, which could develop t he observed relaxer ferroelectric behaviour.