Raman scattering in ferroelectric [NH₂(CH₃)₂]₃Sb₂Cl₉(DMACA)

Abstract

Abstract The Raman spectra (0 - 400 cm−1) of ferroelectric [NH2(CH3)2]3Sb2Cl9 (DMACA) single crystals were studied at temperatures ranging from 100 to 300 K. A temperature dependence study of frequencies of Raman bands around ferroelectric, second order, phase transition at Tc = 242 K revealed a characteristic hardening in frequency of some bands while approaching the transition point from below. Employing the method of O'Brien and Litowitz a temperature dependence of a relaxation time of fluctuations of an order parameter τ = β/(Tc-T) has been extracted.