Large piezoelectric strains from polarization graded ferroelectrics

The potential applications of polarization graded ferroelectrics as high performance sensors and actuators are theoretically investigated. A static bending can be expected in polarization graded ferroelectric plates, forming a vertical displacement. This is due to the built-in strain gradient that arises from the grading of the composition and concomitantly, the spontaneous self-strain. Numerical results of two compositionally graded ferroelectrics, BaTiO3-Ba1-xSrxTiO3 and PbTiO3-Pb1-xZrxTiO3, show a high dynamic response of the displacement under an external electric field, yielding as much as similar to 23% strain at 50 kV/cm in PbTiO3-Pb0.6Zr0.4TiO3, which is comparable to large displacement actuators formed from ceramic/ceramic and ceramic/metal multilayer mesomaterials. (c) 2006 American Institute of Physics.