Acoustic properties of PLZT ceramics studied by Brillouin scattering

Brillouin spectra of lanthanum lead zirconate titanate (Pb_1−x La_x)(Zr_yTi_1−y )O₃ (PLZT-100(x/y/1−y)) relaxor ferroelectric ceramics with the famous composition of PLZT-10/65/35 have been investigated using a high-resolution Brillouin spectroscopy. The central peak of PLZT-10/65/35 appeared below ∼600 K, which is similar to the Burns temperature. The integrated intensity of the central peak grew on cooling and reached its maximum value at around 370 K, which is higher than the dielectric maximum temperatures. The overall shape and width of central peaks did not change in the electric field range of 0–7 kV/cm at room temperature. These observations were discussed in relation with the dynamics of nano-sized polar clusters, which have been suggested as the origin of the complex dynamical behaviors of ferroelectric relaxors.