Intermediate phase between deuteron-glass and antiferroelectric order in the D-RADA system

COEXISTENCE OF PARAELECTRIC/PROTON-GLASS AND FERROELECTRIC (ANTIFERROELECTRIC) ORDERS IN Rb_{1-x}(NH_{4})_{x}H_{2}AsO_{4} CRYSTALS

“…The coexistence of ferroelectric and proton glass states was also observed in other isomorphic ferroelectric-antiferroelectric mixed crystals: [39], and also for deuterated DRADA [11,13].…”

“…Deuteration leads to the narrowing of glass existence range to 0.2 x 0.35 [14][15]41]. [11] is shown in figure 18. A typical behaviour attributed to the transition from the paraelectric to antiferroelectric state is marked at T N = 127 K. This phase transition takes place at the same temperature for different frequencies of the measured electric field.…”

“…The studies of deuteron glass have revealed that, like in a undeuterated crystal, the state of glass may coexist with the ferroelectric or antiferroelectric order [10][11][12][13][14]. Deuteration leads to the narrowing of glass existence range to 0.2 x 0.35 [14][15]41].…”

“…Further studies showed [8][9][10][11][12][13][14][15][16] that the phase diagram is more complex, since paraelectric/proton-glass-ferroelectric or antiferroelectric phases coexist. This paper presents the up to date understanding of the proton-glass state.…”

Two relaxation processes in the inhomogeneous deuterated ferroelectric Rb0.96(ND4)0.04D2AsO4

“…The dispersion related to the freezing of the domain wall motion can be described by E c2 = (1465 ± 169) K (126 meV), and ν 02 = (3.57 ± 0.24) × 10 10 Hz. In the mixed glassy and ferroelectric state the two relaxation processes are described by the Arrhenius equation, but when in the crystals only the glass state is realized, the relaxation processes obey the Vogel−Fulcher law [8,15,16]. The dynamics of the small in size polar clusters − embryos of the glass clusters − is differing from normal glass polar regions with short-range order.…”