Jump to ContentJump to Main Navigation
Show Summary Details
More options …

Zeitschrift für Naturforschung A

A Journal of Physical Sciences

Editor-in-Chief: Holthaus, Martin

Editorial Board: Fetecau, Corina / Kiefer, Claus

IMPACT FACTOR 2017: 1.414

CiteScore 2018: 1.15

SCImago Journal Rank (SJR) 2018: 0.370
Source Normalized Impact per Paper (SNIP) 2018: 0.431

See all formats and pricing
More options …
Volume 49, Issue 1-2


Effect of Deuteration on the Phase Transitions and on the Critical Dynamics in Ammonium Hexachlorometallates

J. Pelzl
  • Institut für Experimentalphysik III, Festkörperspektroskopie, Ruhr-Universität, D-44780 Bochum, FRG
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ C. Dimitropoulos
Published Online: 2014-06-02 | DOI: https://doi.org/10.1515/zna-1994-1-235


Recent and novel data obtained from chlorine NQR measurements on natural and deuterated (NH4)2MCl6 compounds are discussed with special regard to the influence of the ammonium-ion dynamics on the structural stability of these crystals. The temperature dependence (4.2 K to 350 K) of the chlorine NOR frequency vQ and relaxation rates T1-1 , T2-1 obtained from the natural ammonium salts of Sn, Pd, Os, Pb, Te, Se and from the deuterated salts of Sn, Te and Se are analysed. Slight deviations from the normal temperature behaviour of vQ and T1-1 are found in Sn, Pd and Os compounds which stay cubic in the whole temperature range. The ammonium compounds of Pb and Te undergo a structural transformation between 80 K and 90 K from the cubic to a trigonal phase which is distinguished by the preservation of the single line spectrum of the chlorine NQR below rel. The observed divergence of T1-1 at the transition point can be described in terms of a spin-phonon process in the presence of an overdamped soft mode. Deuteration of (NH4)2TeCl6 only slightly affects the transition of Tc2 but leads to new structural changes at lower temperatures. Whereas the natural compound stays trigonal down to 4.2 K the deuterated crystal undergoes two additional structural transformations at Tc2 = 48 K and Tc3 = 28 K which are correlated with a slowing down of the deuteron motion. Approaching Tc2 from above, the spin-lattice relaxation rate and the spin-spin relaxation rate of the chlorine NQR exhibit distinct anomalies which are attributed to limited jumps of the octahedron in a shallow potential. The barrier height of this potential deduced from the chlorine NQR spin-lattice relaxation rate is 400 K. The transition at Tc2 is explained by the condensation in one minimum of this potential. At Tc3 a long range correlation is formed which is accompanied by a rotation of the octahedron about its fourfold axis. A similar mechanism is adopted for the transitions observed in (NH4)2SeCl6 at Tc= 24 K and in (ND4)2 SeCl6 at Tc = 48 K.

Keywords : Nuclear quadrupole resonance; Structural phase transitions; Ammonium-ion dynamics; Hexahalogenometallates; Critical behaviour

About the article

Received: 1993-08-12

Published Online: 2014-06-02

Published in Print: 1994-02-01

Citation Information: Zeitschrift für Naturforschung A, Volume 49, Issue 1-2, Pages 232–246, ISSN (Online) 1865-7109, ISSN (Print) 0932-0784, DOI: https://doi.org/10.1515/zna-1994-1-235.

Export Citation

© 1946 – 2014: Verlag der Zeitschrift für Naturforschung. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0

Citing Articles

Here you can find all Crossref-listed publications in which this article is cited. If you would like to receive automatic email messages as soon as this article is cited in other publications, simply activate the “Citation Alert” on the top of this page.

Masaya Matsuki, Teppei Yamada, Nobuhiro Yasuda, Shun Dekura, Hiroshi Kitagawa, and Nobuo Kimizuka
Journal of the American Chemical Society, 2017
Tetsuo Asaji, Masanori Yoza, and Tomohiro Ishizaka
Journal of Physics: Condensed Matter, 1999, Volume 11, Number 26, Page 5219
J R Shi, Y Kume, B Arnscheidt, Y C Xu, X Wu, and J Pelzl
Journal of Physics: Condensed Matter, 1996, Volume 8, Number 28, Page 5247
Tetsuo Asaji, Yoshio Kume, Kazuhiko Ohya, and Takehiko Chiba
Journal of Physics: Condensed Matter, 1997, Volume 9, Number 12, Page 2563
Osamu Yamamuro, Kenji Okishiro, Takasuke Matsuo, Noriko Onoda-Yamamuro, Kenichi Oikawa, Takashi Kamiyama, Yoshio Kume, and Fujio Izumi
The Journal of Chemical Physics, 1997, Volume 107, Number 19, Page 8004
P Filipek, Z.T Lalowicz, Z Olejniczak, and A Birczyński
Chemical Physics Letters, 2003, Volume 367, Number 1-2, Page 55

Comments (0)

Please log in or register to comment.
Log in