Calorimetric study of the ferroelectric trissarcosine calcium chloride in the range 50-330K

Careful specific heat measurements on trissarcosine calcium chloride (TSCC) have been performed in the range 50-330K, using an adiabatic calorimeter whose calibrated accuracy in the range of measurements reaches 0.1%. The characteristic thermodynamic parameters for the ferro-paraelectric phase transition are: T c =130.27+or-0.03K, Delta H=39.5+or-2 cal mol -1 and Delta S=0.32+or-0.02 cal mol - K -1 . A comparison is made with the Landau and dipolar theories. The critical behaviour agrees with the classical predictions for mod T c -T mod *0.05, but discrepancies appear closer to the transition temperature.