Elastic, dielectric, and piezoelectric characterization of 0.92Pb(Zn_1/3Nb_2/3)O₃-0.08PbTiO₃ single crystal by Brillouin scattering

In this paper, a complete set of elastic, piezoelectric, and dielectric constants of high-quality tetragonal poled 0.92Pb(Zn_1/3Nb_2/3)O₃-0.08PbTiO₃ single crystal grown by the modified flux method is determined using high-resolution Brillouin scattering. A comparison is made between the results obtained by a hybrid method combining ultrasonic and resonant techniques and the results obtained by the Brillouin scattering. The elastic, piezoelectric, and dielectric constants obtained by the two methods are similar. The Brillouin spectrum consists of one longitudinal and two transverse acoustic phonon modes, and the variations of the Brillouin shifts, the full widths at half maximum, and the scattering intensities of these modes with scattering angle θ are investigated. In particular, the transverse acoustic phonon mode at the low-frequency becomes markedly soft from 28.2 GHz to 18.4 GHz and broadens gradually with the increase of θ, while its intensity decreases gradually as compared with that of the original one. The possible origins of the results are discussed.