Abstract: Piezoelectric ceramics that can be used in high temperature actuators. The piezoelectric ceramics have various desirable properties, for example the materials do not depole up to about 400° C. and have large piezoelectric coefficients >400 pm/V. In addition the thickness mode electromechanical coupling coefficient is large, increasing from 0.5 to 0.65 with temperature. The planar electromechanical coefficient is around 0.40 and does not show a significant dependence on temperature. These materials are highly polarizable with remnant polarization around 50 ?C/cm2 and are electrically hard with coercive field above 20 kV/cm. They exhibit single crystal like ferroelectric behavior with square hysteresis loops. Such properties make these materials a piezoelectric ceramic that can be used in stack actuators at high temperatures. Methods for preparing the piezoelectric ceramics are also disclosed.

Abstract: Piezoelectric ceramics that can be used in high temperature actuators. The piezoelectric ceramics have various desirable properties, for example the materials do not depole up to about 400° C. and have large piezoelectric coefficients>400 pm/V. In addition the thickness mode electromechanical coupling coefficient is large, increasing from 0.5 to 0.65 with temperature. The planar electromechanical coefficient is around 0.40 and does not show a significant dependence on temperature. These materials are highly polarizable with remnant polarization around 50 ?C/cm2 and are electrically hard with coercive field above 20 kV/cm. They exhibit single crystal like ferroelectric behavior with square hysteresis loops. Such properties make these materials a piezoelectric ceramic that can be used in stack actuators at high temperatures. Methods for preparing the piezoelectric ceramics are also disclosed.