Ferroelectric and antiferroelectric polarisation switching characteristics of Bi(Mg 0.5Ti 0.5)O 3-PbTiO 3 ceramics

Bi(Mg 0.5Ti 0.5)O 3-PbTiO 3 (BMT-PT) ceramics, with BMT-PT ratios ranging from 70-30 to 50-50, were prepared by a conventional solid state reaction process. The 50-50 BMT-PT ceramic possessed a tetragonal perovskite structure with a c/a ratio of ~1.037. Increasing BMT content led to a reduction of tetragonality and a change of structure to a rhombohedral or pseudo-cubic phase. Dielectric measurements, carried out during heating, indicated the occurrence of two phase transformations, which were identified as relaxor ferroelectric to antiferroelectric (at a temperature in the range from 150-300 °C) and antiferroelectric to paraelectric (at a temperature around 500 °C). The antiferroelectric nature of the 60-40 and 70-30 BMT-PT ceramics in the intermediate temperature range was confirmed by polarisation-electric field hysteresis measurements. © 2009 Springer Science+Business Media, LLC.