Thermally-stimulated discharge of ice electret

The existence of the orientational disorder of water molecules, as evident from the residual entropy, is cruicial to many of the properties of ice; one need only mention the dielectric properties and the shear flow of ice to illustrate its importance. The Third Law of thermodynamics insists that at low enough temperatures the equilibrium state of ice (as, of course, of all states of matter), should be orientationally ordered. The electrical nature of the ordered state may be either ferroelectric, a state in which (ignoring the domain structure) the majority of the dipole vectors are unidirectional, or antiferroelectric, a state in which the dipole vectors are opposite in direction. It has been suggested that the hexagonal ice may transform to a ferroelectric phase near 110°K.^1–5 The evidence was obtained from measurement of the thermally stimulated depolarization (TSD) current in a sample of ice to which an electric field was applied during cooling to 77°K. A peak in current was observed near 110°K and was interpreted as indicating the ferroelectric ordering.