Dielectric and piezoelectric properties of (1-x)(Bi_(1-y)Li_y) X(Sc_(1_y)Sb_y)O_3-xPbTiO_3 high-temperature relaxor ferroelectric ceramics

摘要

BiScO_3-LiSbO_3-PbTiO_3 solid solutions with perovskite structure were prepared by the conventional mixed oxide method. X-ray diffraction showed that a change in symmetry from rhombohedral to tetragonal as the mole fraction of PbTiO_3 larger than 62%. In the vicinity of the morphotropic phase boundary, the ceramics showed enhanced piezoelectric and ferroelectric properties: piezoelectric constant d_(33)-545 pC/N, planar electromechanical coupling factors k_p = 58%, remnant polarization P_r=28.3 μC/cm~2, and the coercive field E_c= 1.8 kV/mm, respectively. The temperature of the permittivity maximum (T_(max)) increased with increasing measure of frequency, over the range of 300-340 ℃, and the ceramics show the relaxor ferroelectric features.