Influence of KF substitution on the ferroelectric phase transition of lead titanate single crystals studied by Brillouin light scattering

Abstract

The elastic properties of KF-substituted perovskite lead titanate (PbTiO 3 ) were investigated by dielectric measurements and Brillouin light scattering. The ferroelectric phase transition occurred at substantially lower temperature due to KF substitution, which was attributed to the modification of the covalency in Pb-O and Ti-O bonds. The longitudinal acoustic (LA) mode of KF-substituted PbTiO 3 showed a frequency softening in the paraelectric phase, which was accompanied by increasing acoustic damping. This indicated that polarization fluctuations responsible for the acoustic anomalies were enhanced by KF substitution.

The intricate lattice dynamics of perovskite oxides

“…Finally, we briefly review the elastic properties of PTO. Figure 24 shows the temperature dependence of the mode frequencies of three acoustic waves of PTO measured at the backscattering [67,68] Chapter 3 -The intricate lattice dynamics of perovskite oxides temperature (~500 o C) indicate the ferroelectric phase transition. An interesting point is that the LA-mode frequency is nearly constant in the paraelectric phase.…”