On the remarkable performance of novel 2-2-type composites based on [011] poled 0.93Pb(Zn1/3Nb2/3)O3-0.07PbTiO3 single crystals

The important role of the anisotropy of elastic and piezoelectric properties in the relaxor-ferroelectric 0.93Pb(Zn1/3Nb2/3)O-3-0.07PbTiO(3) 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 g(33)*, e(33)*, d(h)* and g(h)* within wide ranges along with signs of the piezoelectric coefficients d(3j)((1)) of the 0.93Pb(Zn1/3Nb2/3)O-3-0.07PbTiO(3) single crystal. Experimental d(3j)((1)) values measured by Zhang et al (2006 Appl. Phys. Lett. 89 242908) obey the condition sgn d(33)((1)) = sgn d(31)((1)) = - sgnd(32)((1)) > 0 that has a considerable influence on the piezoelectric performance and hydrostatic parameters of the studied 2-2 and 2-2-0 composites.