Phase coexistence in the deuteron glass Rb0.9(ND4)0.1D2AsO4 proven by neutron diffraction

Abstract

Neutron diffraction technique has been used to study the transitions from the paraelectric (PE) phase to the ferroelectric (FE) one in the deuteron glass crystal Rb0.9(ND4)0.1D2AsO4 (DRADA-10). The crystal shows PE hk0 diffraction spots splitting into spot patterns from domains, 4 spots from 4 FE domain types. A more complex phase behavior that the one corresponding to a typical PE-FE phase transition has been found. Coexistence of FE and PE features together with incommensurate correlations in the low temperature phase has been discovered. The intensity of the spots associated with the FE domains indicates the fraction of the crystal in the low-temperature phase. For DRADA-10 there is a fairly wide temperature range (7-10 K) over which these spots coexisted with spots remaining from the paraelectric phase