New orientation effect in piezo-active 1-3-type composites

This paper demonstrates the influence of the mutual orientation of the poling direction of single-crystal and ceramic components on the properties of 1-0-3 composites containing two ferroelectric components and a piezo-passive polymer. Effective properties to be considered are hydrostatic piezoelectric performance, anisotropy of squared figures of merit and electromechanical coupling factors. We demonstrate that the elastic and piezoelectric anisotropy of the 0-3 connectivity ferroelectric ceramic/polymer matrix with prolate inclusions leads to large hydrostatic piezoelectric coefficients (dh∗ and gh∗) and squared figure of merit (dh∗gh∗) in a 1-0-3 0.67Pb(Mg_1/3Nb_2/3)O₃-0.33PbTiO₃ single crystal/(Pb_1-xCa_x)TiO₃ ceramic/araldite composite with x = 0.20-0.25. In this type of composite values of maxgh∗ ∼10² mV m/N and max(dh∗gh∗) ∼10^-11 Pa^-1 are achieved at specific volume-fraction and rotation-angle ranges due to a new orientation effect in the presence of a highly anisotropic 0-3 matrix. Such composites are of interest for sensor, actuator and energy-harvesting applications.