Orientation effects and figures of merit in advanced 2-2-type composites based on [011]-poled domain-engineered single crystals

The paper reports new results that compare the group of performance figures of merit of piezo-active 2-2-type composites based on [011]-poled domain-engineered (1 - x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 single crystals, where the main crystallographic axes in the crystal layers are rotated to tailor effective electromechanical properties and related parameters. Examples of the orientation and volume-fraction dependences of the figures of merit are analysed for the first time for the system of 2-2 single crystal/polymer composites and 2-0-2 single crystal/corundum ceramic/polymer composites at x = 0.0475-0.09. The connections between the piezoelectric coefficients, energy-harvesting figures of merit and modified figures of merit (j = 1, 2 and 3) are highlighted during rotation of the main X and Y crystallographic axes around the Z axis of the crystal layers. A similar orientation behaviour of, and and their large anisotropy are studied at specific volume fractions of the single-crystal component and for a variety of microgeometric architectures of a corundum ceramic/polymer layer with 0-3 connectivity. Maxima of the longitudinal parameters, and at x = 0.0475-0.09 and constant volume fraction of the single-crystal component of the 2-2-type composites are observed in a relatively narrow orientation range. A new performance diagram is built to show regions of a large anisotropy of and in a 2-0-2 composite and, as a result of the large piezoelectric coefficients and figures of merit, the composites show significant potential in the field of piezoelectric energy-harvesting and sensor applications. This journal is