Structure, electrical properties, and depoling mechanism of BiScO3-PbTiO3-Pb(Zn1/3Nb2/3) O3 high-temperature piezoelectric ceramics

The structure, electrical properties, and depoling mechanism of the (0.95-x) BiScO3-xPbTiO(3) -0.05Pb(Zn1/3Nb2/3)O-3 (BS-xPT-PZN, x=0.54-0.70) compositions close to the morphotropic phase boundary (MPB) have been systematically investigated as a function of PbTiO3 content (x). The phase approached from the rhombohedral toward the tetragonal phase when the PbTiO3 contents increased. The composition with high PT content exhibited normal ferroelectric behavior while it showed a diffused phase transition characteristic as PT decreased. In the vicinity of the MPB, the ceramics showed enhanced piezoelectric, electromechanical, and ferroelectric properties with piezoelectric constant d(33)=490 pC/N, planar electromechanical coupling factors k(p)=57.4%, remnant polarization P-r=40.1 mu C/cm(2), and coercive field E-c=28.5 kV/cm with a high transition temperature T-m similar to 417 degrees C, respectively. The thermal depoling experiments of the polarization for samples with different phase structures were investigated and the possible depoling mechanism was discussed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3525995]