Showing papers by "Robert Blinc published in 1973"
54 citations
TL;DR: Underdamped soft tunnelling modes, which disappear on deuteration, are observed in KHZP04 type crystals below Tc in addition to a central mode which exists both above and below TC as discussed by the authors.
Abstract: Underdamped soft tunnelling modes, which disappear on deuteration, are observed in KHZP04 type crystals below Tc in addition to a central mode which exists both above and below Tc. These results can be understood in terms of a Bloch type description of pseudo-spin motion.
Ungedampfte soft-Tunnelmoden, die bei Deuterierung verschwinden, werden in Kristalen vom KH2PO4-Typ unterhalb Tc zusatzlich zu einer Zentralmode, die sowohl oberhalb als auch unterhalb Tc existiert, beobachtet. Dieses Ergebnis lasit sich mit einer Bloch-Beschreibung der Pseudo-Spin-Bewegung verstehen.
22 citations
TL;DR: In this paper, the temperature dependence of the 75As dipolar spin-lattice relaxation time in both para-and ferroelectric KH2AsO4 and CsH2AO4 has been determined and the results are related to the microscopic model of the phase transition.
Abstract: The temperature dependence of the 75As dipolar spin‐lattice relaxation time in both para‐ and ferroelectric KH2AsO4 and CsH2AsO4 has been determined and the results are related to the microscopic model of the phase transition. The temperature dependences of 75As NQR frequency and linewidth in KD2AsO4 and CsD2AsO4 and the corresponding Rb salts have been as well studied and a good agreement has been found between the theoretical and experimental results.
18 citations
TL;DR: In this article, the application of rotating-and dipolar-frame proton-relaxation measurements for the determination of fast quadrupolar relaxation rates of nonresonant spins $S$, the signals of which are too weak to be measured by the conventional NMR technique, is discussed.
Abstract: The application of rotating- and dipolar-frame proton-relaxation measurements for the determination of fast quadrupolar relaxation rates of nonresonant spins $S$, the signals of which are too weak to be measured by the conventional NMR technique, is discussed Both the case where the proton-$S$ cross-relaxation rate is fast as compared to the $S$-spin-lattice relaxation rate and the case where it is slow are treated The method is applied to ${\mathrm{Ag}}_{2}$${\mathrm{H}}_{3}$I${\mathrm{O}}_{6}$ and ${(\mathrm{N}{\mathrm{H}}_{4})}_{2}$${\mathrm{H}}_{3}$I${\mathrm{O}}_{6}$ The $T$ dependence of the $^{127}\mathrm{I}$ quadrupolar spin-lattice relaxation rates is extracted from the $T$ dependence of the proton dipolar- and rotating-frame spin-lattice relaxation times The iodine-spin-lattice relaxation times are found to be very short and seem to be controlled by electric-field-gradient (EFG) fluctuations due to the motion of protons between the two equilibrium sites in the O-H\char22{}O bonds Using the known values of the static $^{127}\mathrm{I}$ EFG tensor, the O-H\char22{}O proton intrabond jump time $\ensuremath{\tau}$ was found to be of the order of ${10}^{\ensuremath{-}10}$ sec at room temperature, ie, of the same order as in K${\mathrm{H}}_{2}$P${\mathrm{O}}_{4}$-type ferroelectrics
17 citations
TL;DR: In this paper, the phase transitions in KDA, KD†A, RDA and CDA were observed to be of the first order and the static dielectric properties of these ferroelectrics resemble those of KD†P.
17 citations
TL;DR: In this paper, the 75As EFG tensors corresponding to the four nonferroelectric H2AsO4 Slater configurations have been determined and the correctness of the antiferroelectric proton ordering scheme proposed by Nagamiya is demonstrated.
Abstract: The 75As EFG tensors corresponding to the four ``nonferroelectric'' H2AsO4 Slater configurations have been determined and the correctness of the antiferroelectric proton ordering scheme proposed by Nagamiya is demonstrated. A comparison of the theoretical and experimental temperature dependences of the 75As NQR frequencies for T > Tc seems to show that the Slater parameter e has the same sign in ADA as in KDA. The antiferroelectric transition thus seems to be triggered by long range dipole‐dipole forces rather than by short range ones.
12 citations
TL;DR: In this article, the pure quadrupole resonance spectrum of 17 O has been measured in a 10% enriched KH 2 PO 4 sample at 190°K at at 77°K and the results can be interpreted in terms of a double minimum type O-H-O hydrogen bond potential, where the protons above T c rapidly fluctuate between the two equilibrium sites.
8 citations
TL;DR: A comparison of the quadrupole perturbed deuteron magnetic resonance spectra of the α,β, and γ phase of partially deuterated sodium trihydrogen selenite crystals was made in this article.
5 citations
3 citations