Effects of strontium on the dielectric and piezoelectric properties of Sm-modified PbTiO₃ ceramics

The Sm-modified lead titanate ceramics with a composition of (Pb 0.88 - x Sr x Sm 0.08 ) (Ti 0.98 Mn 0.02 )O 3 ; x = 0.05~0.25 were prepared by conventional mixed-oxide method. The dielectric and piezoelectric properties of these doped ceramics were measured at room temperature. Microstructural and compositional analyses have been carried out using SEM and XRD. The experiments successfully showed that Sr additive is helpful to obtain much higher thickness electromechanical coupling coefficient, k t (>0.55), than that of conventional PbTiO 3 based ceramics and still keep small planar electromechanical coupling coefficient, k p . On the other hand, the Sr additives help to reduce the lattice anisotropy efficiently. The temperature coefficient of frequency and the Curie point versus the amount of Sr composition were also investigated.