Polarization orientation effect and combination of electromechanical properties in advanced0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 single crystal/polymer composites with 2–2 connectivity

Abstract

A comparative study on the effective piezoelectric properties and hydrostaticpiezoelectric response is first carried out for advanced 2–2 composites based onsingle crystals of relaxor-ferroelectric solid solutions. Different orientationsof domains and different poling directions of components are taken intoconsideration in the analysis of the effective longitudinal piezoelectric coefficientsd33*,e33*,g33* and hydrostaticpiezoelectric coefficients dh*, eh* and gh*. The important role of the polarization orientation effect and the effectof combination of the electromechanical properties in attaining the largeeffective parameters is shown for the parallel-connected 2–2 single-domain0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3/polyvinylidene fluoride composite. In particular, near extremum points of the effectiveparameters, this composite is characterized by the piezoelectric coefficientsg33*≈500 mV m N−1,|dh*|≈400 pC N−1,|eh*|≈40 C m−2,and gh*≈400 mV m N−1. Three piezo-sums are first found to describe major contributions of the piezoelectric coefficientsdij*,eij* andgij* todh*,eh* andgh*, respectively, in the vicinity of absolute maxima (minima) of the aforementionedhydrostatic parameters. Advantages concerned with the presence of the single crystal(either single-domain or polydomain) in the studied 2–2 composites are discussed inconnection with their piezoelectric activity, sensitivity and hydrostatic response.