Detailed Raman scattering investigation of LiKSO₄ in phases II and III across the transition temperatureT_c ≃ 700 K is reported. Abrupt change in frequency and line width of the external and internal modes have been observed. Analysis of the results suggests lithium positional disorder and sulphate orientational disorder in the high temperature phase (II). The results also throw some light on the existence of twin domains in the crystal.

We have measured the kinetics of phase transition in LiKSO₄ (C₆⁶→C_3v⁴;T_c∼201 K) by monitoring the time-dependent change in Raman intensity of selected vibrational lines at various temperatures in the transformed phaseC_3v⁴. We find that the observed growth curves for several temperatures display a nearly universal shape when plotted against a suitably scaled time parameter. We interpret our results in terms of a phenomenological model of nucleation and growth.