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Pis'ma v Zhurnal Èksperimental'noi i Teoreticheskoi Fiziki, 2003, Volume 78, Issue 2, Pages 95–98
(Mi jetpl2496)
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This article is cited in 1 scientific paper (total in 1 paper)
Anomalous behavior of the velocity of hypersonic acoustic phonons in (NH$_4)_3$H(SO$_4)_2$ crystals
S. G. Lushnikova, A. I. Fedoseeva, L. A. Shuvalovb, H. Shmidtc a Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg
b Institute of Cristallography Russian Academy of Sciences, Moscow
c Montana State University
Abstract:
The velocity of quasi-longitudinal acoustic (QLA) phonons in (NH$_4)_3$H(SO$_4)_2$ (TAHS) crystals was studied by Brillouin scattering in the temperature range from 295 to 430 K. It was found that the QLA phonon velocity in the vicinity of a superionic ferroelastic phase transition ($T_c=413\,$K) exhibits anomalous temperature dependence. At $T<T_c$, an additional contribution is separated from the temperature dependence of the hypersound velocity, the behavior of which is correlated with variations of the conductivity of a TAHS crystal. Based on an analysis of the experimental data, a thermoactivation mechanism explaining the anomalous behavior of the QLA phonon velocity is proposed and the corresponding activation energy is estimated.
Received: 24.06.2003
Citation:
S. G. Lushnikov, A. I. Fedoseev, L. A. Shuvalov, H. Shmidt, “Anomalous behavior of the velocity of hypersonic acoustic phonons in (NH$_4)_3$H(SO$_4)_2$ crystals”, Pis'ma v Zh. Èksper. Teoret. Fiz., 78:2 (2003), 95–98; JETP Letters, 78:2 (2003), 84–87
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https://www.mathnet.ru/eng/jetpl2496 https://www.mathnet.ru/eng/jetpl/v78/i2/p95
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Abstract page: | 137 | Full-text PDF : | 46 | References: | 37 |
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