EVOLUTION OF DOMAINS AND THERMAL HYSTERESIS EFFECTS IN THE PYROCHLORE-STRUCTURE FERROELECTRIC CD2NB2O7

An analysis of the thermally induced domain behavior in Cd2Nb2O7 under cooling and heating in the dark has revealed that below T-c the coexi stence of ferroelectric-ferroelastic domains of different types is acc ompanied by irreversible changes in the domains of the previous phase (T-c<T< T-s). Interaction of domains with dislocations and other latti ce defects causes thermal hysteresis in the phase transition region ne ar T-s and T-c typical of the ''superheated'' ferroic state. (C) 1997 American Institute of Physics.