New high temperature morphotropic phase boundary piezoelectric ceramics

New morphotropic phase boundary (MPB) piezoelectrics with ferroelectric phase transitions (T/sub c/) exceeding that of PbZrO/sub 3/-PbTiO/sub 3/ (PZT) were investigated. Based on a perovskite tolerance factor - T/sub c/ relationship, new high T/sub c/ MPB systems were projected in Bi(Me)O/sub 3/-PbTiO/sub 3/ systems, where Me is a relatively large B/sup +3/-site cation. For the (1-x)BiScO/sub 3/-(x)PbTiO/sub 3/ 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/sub c/ of /spl sim/450/spl deg/C was determined with higher T/sub c/s projected with lower tolerance factor systems.