Anisotropy in domain engineered 0.92Pb(Zn_1/3Nb_2/3)O₃-0.08PbTiO₃ single crystal and analysis of its property fluctuations

The orientation dependence of slowness and electromechanical coupling coefficients of 0.92Pb(Zn_1/3 Nb_2/3)O₃-0.08PbTiO₃ (PZN-8%PT) domain engineered single crystal was analyzed based on the measured complete set of elastic, piezoelectric, and dielectric constants. There exist one quasi-longitudinal, one quasi-shear, and one pure shear wave in each of the [100]-[010], [010]-[001], and [001]-[110] planes. The slowness of the quasi-shear wave exhibits strong anisotropy in all three planes, and the coupling coefficient k₃₃ and k₃₁ reach their maximum in [001] and [110] directions of cubic axis, respectively. Because the composition of PMN-8%PT system is very close to the morphotropic phase boundary, the extraordinary large piezoelectric coefficients d₃₁ and d₃₃, and high coupling coefficient k₃₃ are very sensitive to compositional variation. We have performed error analysis and proposed an improved characterization scheme to derive a complete data set with best consistency.