Doping effects of strontium on the piezoelectric and dielectric properties of Ca additive Sm-modified PbTiO3 ceramics

Effects of Sr dopants on the piezoelectric and dielectric properties of (Ca, Sm)-modified PbTiO3 ceramics have been investigated. The modified lead PbTio(3) ceramics with a composition of (Pb-0.73-Ca0.15SrxSm0.08)(Ti0.98Mn0.02)O-3; X = 0.05-0.1 were prepared by conventional mixed-oxide methods with sintering temperature at 1200degreesC. Microstructural and compositional analyses of these doped ceramics have been carried out using XRD and SEM. We successfully showed that Sr additive is helpful to reduce the lattice constant and obtain higher thickness electromechanical coupling coefficient, k(t)(>0.55), and still keep small planar electromechanical coupling coefficient, k(p). In addition, Sr additives varied the temperature coefficient of resonant frequency (TCF) value from a positive value (+34 ppm/degreesC) to a negative value (-47.2 ppm/degreesC), and there exists a point with the TCF value close to zero between Sr = 0.06-0.065. (C) 2003 Elsevier B.V. All rights reserved.