Critical Slowing-Down and Static Dielectric Constant of Monoclinic RbD₂PO₄

Critical Slowing Down in Ferroelectric Pyridinium Tetrafluoroborate

“…When compared with that in TGS [22], the critical slowing down in PyBF 4 occurs in relatively low frequencies, however, it has been observed at even lower frequencies in other materials [23]. For hydrogen-bonded ferroelectrics the critical slowing down dynamics is found in the range of GHz [12,17,24,25]. We found no influence of deuteration on the Curie temperature of PyBF 4 , so the origin of ferroelectricity is not caused by ordering of hydrogen bonds.…”

EPR Study of Monoclinic RbD2PO4Monocrystal Doped with Cr5+Ion

“…In addition we observe Cr5+-Cr 5 + pair EPR spectrum of the two coupled centers through O-D... O path, line splitting of which at T*, well below T1 11 , is due to the anisotropic part of exchange coupling J'. It has been shown by dielectric measurements [6] that the strength of one-dimensionality in DRDP is equal to 1.43 x 104 compared with the value 1.33 x 10 2 of CsH2PO4 (CDP) crystal. It is worth noticing that the coupling of four Cue+ paramagnetic centers in CDP was also observed by us [19,20].…”

“…Deuterated single crystal of monoclinic DRDP were grown following the procedure described elsewhere [6] and in addition 0.06 wt% of K2Cr2O7 was added to the mother solution.…”

“…Recently complex dielectric measurements [6] in the frequency range 106-106 Hz as well as NMR studies of 87 Ró [17] revealed the pseudo one-dimensional nature of the correlations in the deuterium motion between the two potential minima in the 0-D...0 bonded chains along b-axis. This motion freezes out at TII.…”

Crystal Structures of Tetragonal and Monoclinic RbD2PO4Crystals

“…The space groups are P2 1 /m, P2 1 /a and P2 1 in the phases I, II and III, respectively [9,10]. The II-III phase transition has the large isotope effect with the temperature shift of 68 K, whereas the I-II phase transition exhibits the negative isotope effect with −13 K [11,12]. The dielectric study has reported that the dielectric constant shows a remarkable deviation from the Curie-Weiss law in the phase II, [4] while the deviation is small in the phase I [11].…”