Large piezoelectric strains from polarization graded ferroelectrics

Abstract

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, BaTi O3 - Ba1-x Srx Ti O3 and PbTi O3 - Pb1-x Zrx Ti O3, show a high dynamic response of the displacement under an external electric field, yielding as much as ∼23% strain at 50 kVcm in PbTi O3 - Pb0.6 Zr0.4 Ti O3, which is comparable to large displacement actuators formed from ceramic/ceramic and ceramic/metal multilayer mesomaterials. © 2006 American Institute of Physics.