Fabrication of Sm- and Mn-doped lead titanate ceramic powder and ceramics by sol–gel methods

Samarium- and manganese-doped lead titanate (Pb0.85Sm0.1Ti0.98Mn0.02O3, PSmT) ceramic powder was prepared by sol–gel method. The particle size of the sol–gel powder was about 250 nm. PSmT ceramics were also fabricated from the fine powder. The sintering temperature of these ceramics was lower than that of the ceramics made from mixed oxides. The X-ray diffraction patterns show that the ceramics have a pure tetragonal crystal structure. The c and a of the unit cell were 4.068 and 3.897 Å, respectively. The piezoelectric and dielectric properties were measured by using an impedance analyzer and a d33 meter. The dielectric permittivity, piezoelectric constant and thickness electromechanical coupling coefficient kt of the ceramics were 180, 51 and 0.44 pC N−1, respectively. The planar electromechanical coupling coefficient kp value was lower than 0.05.