PbTiO3 addition and internal dynamics in Pb(Zn13Nb23)O3 crystal studied by Raman spectroscopy

Abstract

We present the results of the Raman study of lattice dynamics and development of mesoscopic range order in a relaxor ferroelectric Pb(Zn13Nb23)O3 crystal containing 4.5% of PbTiO3 as it is cooling down from 1000to100K. As in the other relaxors, the relaxor state develops in four stages separated by three temperatures: Burns temperature TB∼800K, intermediate temperature Td∼550K, and freezing temperature Tf∼370K. However, the mixed crystal shows significant differences compared to the nominally pure one. First, there is a dramatic decrease of the scattered intensity above TB; second, a significant asymmetry of the polarizability tensor occurs near the Td reflected by polarization properties of the central peak; third, a softening of line B (∼780cm-1) is found in the neigborhood of Td; fourth, essentially different in each case is the splitting of the broad band E (∼560cm-1), and its value can serve as an indicator of the order parameter in the system. © 2005 The American Physical Society.