Anomalous variations in elastic properties of lead zirconate niobate-lead titanate single crystals in the vicinity of its ferroelectric phase transition
1 Physics Division, Directorate of Science, PINSTECH - Islamabad 45650, Pakistan
2 Ultra-Broadband Spectroscopy Laboratory, Institute of Materials Science, University of Tsukuba Tsukuba, Ibaraki 305-8573, Japan
Received: 4 February 2014
Accepted: 25 February 2014
The acoustic phonon mode anomalies in the paraelectric phase of tetragonal and rhombohedral (1 − x)Pb(Zn1/3Nb2/3)O3−xPbTiO3 single crystals were systematically investigated by Brillouin light scattering measurements. The inverse relaxation time in the paraelectric phase of both crystals showed a stretched-type slowing-down temperature dependence approaching the structural phase transition temperature instead of a normal critical slowing-down. The observed anomalous part of the elastic constant in the paraelectric phase of the tetragonal crystal in the vicinity of , exhibited a -type dependence in the temperature range from to . On the other hand, the elastic constant of the rhombohedral ferroelectric crystal exhibited a deviation from such a temperature dependence. This was attributed to the interaction of acoustic phonon modes with strong polarization fluctuations and elastic deformation arising from the complex dynamics of polar nanoregions.
PACS: 77.80.Jk – Relaxor ferroelectrics / 78.35.+c – Brillouin and Rayleigh scattering; other light scattering / 77.80.B- – Phase transitions and Curie point
© EPLA, 2014