Determination of elastic, piezoelectric and dielectric properties of Pb(Zn_1/3Nb_2/3)O₃-PbTiO₃ single crystals

We report a set of measured material properties of Pb(Zn_1/3Nb_2/3)O₃-PbTiO₃(PZN-PT) multi-domain single crystals. While deriving these properties, it was assumed that the rhombohedral PZN-PT crystals have 4 mm symmetry when it is poled along the [001] of the original cubic direction. Samples with three pair of faces oriented in [001], [010] and [100] were made for the resonance measurements and additional samples with the orientations of [001], [110] and [1 1̄ 0] were made for the ultrasonic measurements. Complete sets of the material constants were obtained for PZN-4.5%PT and PZN-8%PT. The coupling coefficient k₃₃ is 94% for the PZN-8%PT and 90% for the PZN-4.5%PT. A piezoelectric constant d₃₃ of 2300 pC/N was obtained for the PZN-8%PT sample. These values are very encouraging for designing broadband ultrasonic transducers. Based these measurement results, the directional dependence of phase velocities and electromechanical coupling coefficients were analyzed. The calculations indicate that the coupling coefficient k₃₁ and k₃₃ has a maximum in the [110] and [001], respectively, a result consistent with the direct measurements. Errors in these measurements were also analyzed.