New high temperature morphotropic phase boundary piezoelectrics based on Bi(Me)O3-PbTiO3 ceramics

New morphotropic phase boundary (MPB) piezoelectrics, with ferroelectric phase transition (T-c) exceeding that of PbZrO3-PbTiO3 (PZT), were investigated. Based on a perovskite tolerance factor-T-c relationship, new high T-c MPB systems were projected in the Bi(MC)O-3-PbTiO3 system, where Me is a relatively large B+3-site cation. For the (1 - x)BiScO3-(x)PbTiO3 solid solution, a MPB was found at x-0.64 separating the rhombohedral and tetragonal phases, with correspondingly enhanced dielectric and piezoelectric properties. A transition temperature T-c of similar to 450 degreesC was determined with evidence of T-c's on the order of greater than or equal to 600 degreesC in the BiInO3 and BiYbO3 analogues, though issues of perovskite stability remain for the smaller tolerance end-member systems.