Specific Heat Anomaly of Ferroelectric Cadmium Niobate at the Curie Temperature

The anomalous specific heat of ferroelectric Cd₂{Nb}₂O₇ has been measured in the region of its Curie temperature, Tc=193^∘K, using a vacuum adiabatic calorimeter. The values of the transition energy and the transition entropy change are 18±{}2 cal/mole and 0.09±{}0.01 cal/^∘{}K-mole, respectively. A comparison between the experimental values of the transition entropy change, the spontaneous polarization, and the Curie constant is made.