Central Peak of Ferroelectric LiH3(SeO3)2 near the Melting Point Studied by Raman Scattering

Abstract

The central peak of the Raman spectrum of ferroelectric LiH3(SeO3)2 was observed as a function of temperature from 300 K to the melting point (383 K). With increasing temperature, the linewidth takes a minimum around 360 K and then shows anomalous broadening near the melting point. The temperature dependence of the linewidth is decomposed into two components; one component decreases linearly with temperature and the other one shows an anomalous increase toward the melting point. The analysis shows that the former is caused by the critical slowing down of the fluctuating electric polarizations in the ferroelectric phase and the latter by the activation of the ionic motion due to the premelting phenomena