The first precise measurements of specific heat changes have been performed for a novel ferroelectric material, (NH4)2H2P2O6 by means of an ac calorimeter. The paraelectric ferroelectric phase transition at about 177.5 K of second order type is revealed and described by the Landau model using specific heat and linear birefringence data. Thermal parameters (such as the excess enthalpy ( H) and the excess entropy ( S)) of the continuous phase transition were estimated and discussed. The calorimetric measurements indicate a complex mechanism of the ferroelectric transition, both a displacive and order disorder contributions are suggested.
Compounds
#
Formula
Name
1
H10N2O6P2
diammonium hypodiphosphate
Datasets
The table above is generated from the ThermoML associated json file (link above).
POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied;
the numbers refer to the table of compounds on the left.