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

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 (χ −1 ) associated with the phase transition is related to the hard‐mode frequency shift (ω Q ) as ${\Delta}(\chi^{-1}) = R\omega_{\rm Q}^{2}$ , where the proportionality constant R can be determined from the experimental data. This relation ${\Delta}(\chi^{-1}) = R\omega_{\rm Q}^{2}$ between the changes in χ −1 and $\omega_{\rm Q}^{2}$ 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 × 10 −7 cm 2 in the antiferroelectric phase. Copyright © 2006 John Wiley & Sons, Ltd.