Specific Heat Anomaly of Ferroelectric Cadmium Niobate at the Curie Temperature

Abstract

The anomalous specific heat of ferroelectric ${\mathrm{Cd}}_{2}$${\mathrm{Nb}}_{2}$${\mathrm{O}}_{7}$ has been measured in the region of its Curie temperature, ${T}_{c}=193\ifmmode^\circ\else\textdegree\fi{}$K, using a vacuum adiabatic calorimeter. The values of the transition energy and the transition entropy change are 18\ifmmode\pm\else\textpm\fi{}2 cal/mole and 0.09\ifmmode\pm\else\textpm\fi{}0.01 cal/\ifmmode^\circ\else\textdegree\fi{}K-mole, respectively. A comparison between the experimental values of the transition entropy change, the spontaneous polarization, and the Curie constant is made.