Dielectric and Dilatometric Properties of NH(CH_3)_3CuCl_3·2H_2O Low Dimensional Ferroics

Yu. Korchaka, V. Kapustianika, A. Batiuka, I. Girnykb, Z. Czaplac and S. Dackoc aFerroics Physics Laboratory, Electronics Department, Lviv I. Franko National University, Tarnavskogo st. 107, 79017 Lviv, Ukraine bInstitute of Physical Optics, Dragomanova st. 23, 79005 Lviv, Ukraine cInstitute of Experimental Physics, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław, Poland

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Received: May 10, 2004

On the basis of dilatometric and dielectric investigations of\linebreak NH(CH3)3CuCl3·2H2O crystals the earlier unknown phase transition with considerable temperature hysteresis was found at T1c=198 K and T1h=223 K, respectively, in cooling and heating runs. Existence of the characteristic dielectric dispersion was revealed within the high-temperature phase. It corresponds to the single dielectric relaxator below 250 K as well as to co-existence of two relaxators above this temperature. The determined values of the activation energy and relaxation time are characteristic of the co-operative reorientation of the trimethylammonium cation (high-frequency relaxator) whereas the combined reorientation motions of the CuCl2·2H2O chains would be responsible for the low-frequency relaxation process. It was found that the above mentioned quasi-Debye type processes are involved into the mechanisms of the protonic conductivity.

DOI: 10.12693/APhysPolA.106.39 PACS numbers: 64.70.-p