Temperature Evolution of Inelastic Synchrotron Radiation Scattering in PbZr0.985 Ti0.015O3in the Vicinity of M-Point

The paper presents the study of the temperature evolution of the phonon spectra of the PbZr
0.985
Ti
0.015
O
3
in the vicinity of the M-point of the Brillouin zone in the temperature range from 518 K to 800 K using inelastic X-ray scattering (IXS). The spectra provided by IXS at temperatures far above the transition temperature can be well described by the combination of coupled transverse acoustic and antiferrodistortive “oxygen” modes. Additional contributions from the longitudinal acoustic and some high-energy modes were found. However, this model does not correctly describe the data at 518 K close to the transition temperature T
tr
≈513 K, due to the emergence of the additional central peak. The model describing data in the whole temperature range is proposed. Assumptions about the nature of the central peak arising close to transition temperature are made.