On the remarkable performance of novel 2–2-type composites based on [0 1 1] poled 0.93Pb(Zn1/3Nb2/3)O3–0.07PbTiO3single crystals

The important role of the anisotropy of elastic and piezoelectric properties in the relaxor-ferroelectric 0.93Pb(Zn1/3Nb2/3)O3–0.07PbTiO3 single crystal poled along [0 1 1] of the perovskite unit cell has been stated in connection with the formation of the piezoelectric response of the 2–2-type piezo-active composites based on this single crystal. Different examples of the 2–2 single crystal/polymer and 2–2–0 single crystal/porous polymer composites have been studied in this work. Based on the non-monotonic volume fraction and orientation dependences of effective piezoelectric coefficients and figures of merit of the 2–2-type composites, we have shown their advantages. These advantages are associated with a presence of high piezoelectric activity and sensitivity, with variations of the effective piezoelectric coefficients , , and within wide ranges along with signs of the piezoelectric coefficients of the 0.93Pb(Zn1/3Nb2/3)O3–0.07PbTiO3 single crystal. Experimental values measured by Zhang et al (2006 Appl. Phys. Lett. 89 242908) obey the condition sgn that has a considerable influence on the piezoelectric performance and hydrostatic parameters of the studied 2–2 and 2–2–0 composites.