Mechanism of the Ferroelectric Phase Transition in Tris-Sarcosine Calcium Chloride

Consistency between the Debye dispersion in the close vicinity of Tc and the resonant type dispersion of TO soft phonon mode observed in TSCC was examined through comparison of the dynamical and the static quantites by extrapolation. Noticeable discrepancy was found between the two dispersions. X-ray crystal structure analysis revealed a disordered structure above Tc. The structure below Tc is well approximated with one of the two of atomic configurations above Tc. Soft mode contribution was not detected in the mean square thermal amplitude in consistent with the small extrapolated value of the static dielectric constant of the resonant type dispersion.