Nondegenerate hard-mode Raman studies of phase transition in antiferroelectric lead ytterbium niobate-based perovskite compound

Abstract

By using Slater's phenomenological theory of atomic lattice dynamics, general results for the nondegenerate hard mode of phase transition are rederived in a simpler form. The change in inverse dielectric susceptibility (chi(-1)) associated with the phase transition is related to the hard-mode frequency shift (omega(Q)) as Delta (chi(-1)) = R omega(2)(Q), where the proportionality constant R can be determined from the experimental data. This relation Delta(chi(-1)) = R omega(2)(Q) between the changes in chi(-1) and omega(2)(Q) was verified for the antiferroelectric phase transition observed in 0.94PYN [Pb(Yb(1/2)Nb(1/2))O(3)]-0.06PT[PbTiO(3)], with the proportionality constant R as -1.6 X 10(-7) cm(2) in the antiferroelectric phase. Copyright (C) 2006 John Wiley & Sons, Ltd.