Preparation and Characterization of High Temperature Perovskite Ferroelectrics in the Solid-Solution (1-x)BiScO₃–xPbTiO₃

The dielectric and piezoelectric properties of the new perovskite solid solution system (1 - x)BiScO3-xPbTiO(3) were investigated. This system is representative of a new group of high temperature piezoelectrics that includes Bi(Me)O-3-PbTiO3, where Me+3 is a relatively large cation, Sc, Y, Yb, In. etc., and combinations thereof. In the (1 - x)BiScO3-xPbTiO(3) series, perovskite stability was achieved for x > 50 mol% PbTiO3 being ferroelectric rhombohedral and transforming to ferroelectric tetragonal in the region x = 64 mol% PbTiO3, designated as the morphotropic phase boundary (MPB). Analogous to (1 - x)PbZrO3-xPbTiO(3) (PZT), the dielectric and piezoelectric properties were enhanced for compositions near the MPB. Piezoelectric coefficient d(33) values reached 450 pC/N, comparable to soft PZT's with a transition temperature of 450degreesC. more than 100degreesC higher than commercial PZT. The combination of high Tc and excellent piezoelectric activity make (1 - x)BiScO3-xPbTiO(3) materials candidates for high temperature, and temperature stable actuators and transducers.