Abstract
The distribution function of relaxation times is reconstructed from the dielectric loss spectrum measured over a wide range of frequencies for a 4-n-pentyl-4′-cyanobiphenyl (5CB) liquid crystal. It is demonstrated that the distribution function for the isotropic and nematic phases is asymmetric in shape. Comparison shows that the reconstructed distribution function is in qualitative agreement with similar functions that are analytically derived from the Cole-Davidson and Havriliak-Negami empirical equations. The specific features observed in the behavior of the distribution function with a variation in the angle between the direction of polarization of a microwave electric field and the director of the liquid-crystal molecules are analyzed. A complex dependence of the permittivity for the liquid crystal in the range of ultrahigh frequencies is explained in terms of additional relaxation mechanisms associated with different motions of molecular fragments of alkyl chains.
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B. A. Belyaev, N. A. Drokin, V. F. Shabanov, and V. N. Shepov, Fiz. Tverd. Tela (St. Petersburg) 45(3), 567 (2003) [Phys. Solid State 45 (3), 598 (2003)].
B. A. Belyaev, N. A. Drokin, V. F. Shabanov, and V. A. Baranova, Fiz. Tverd. Tela (St. Petersburg) 46(3), 554 (2004) [Phys. Solid State 46 (3), 574 (2004)].
B. A. Belyaev, N. A. Drokin, and V. F. Shabanov, Fiz. Tverd. Tela (St. Petersburg) 46(3), 559 (2004) [Phys. Solid State 46 (3), 579 (2004)].
E. M. Aver’yanov, Local Field Effects in Optics of Liquid Crystals (Nauka, Novosibirsk, 1999) [in Russian].
H. Fröhlich, Theory of Dielectrics, (Oxford Univ. Press, Oxford, 1958; Inostrannaya Literatura, Moscow, 1960).
B. A. Belyaev, N. A. Drokin, V. F. Shabanov, and V. N. Shepov, Zh. Tekh. Fiz. 72(4), 99 (2002) [Tech. Phys. 47 (4), 470 (2002)].
F. Alvarez, A. Alegria, and H. Colmenero, Phys. Rev. B 44(14), 7306 (1991).
F. D. Morgan and D. P. Lesmes, J. Chem. Phys. 100(1), 671 (1994).
V. A. Valenkevich, M. S. Mitsek, and O. I. Gudkov, Izv. Vyssh. Uchebn. Zaved., Fiz. 25(3), 37 (1982).
S. A. Ktitorov, Pis’ma Zh. Tekh. Fiz. 29(22), 74 (2003) [Tech. Phys. Lett. 29 (11), 956 (2003)].
M. A. Leshchenko and Yu. M. Poplavko, Ukr. Fiz. Zh. 73(6), 898 (1992).
J. R. Macdonald, J. Chem. Phys. 102(15), 6241 (1995).
A. Bello, E. Laredo, and M. Grimau, Phys. Rev. B 60(18), 12764 (1999).
Y. Imanishi, K. Adachi, and T. Kotaka, J. Chem. Phys. 89(12), 7593 (1988).
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Translated from Fizika Tverdogo Tela, Vol. 47, No. 9, 2005, pp. 1722–1726.
Original Russian Text Copyright © 2005 by Belyaev, Drokin, Shabanov.
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Belyaev, B.A., Drokin, N.A. & Shabanov, V.F. Distribution function of relaxation times for a 4-n-pentyl-4′-cyanobiphenyl liquid crystal. Phys. Solid State 47, 1791–1796 (2005). https://doi.org/10.1134/1.2045369
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DOI: https://doi.org/10.1134/1.2045369