AC electrical properties and dielectric relaxation of [N(C3H7)4]2Cd2Cl6, single crystal

The bis tetrapropylammonium hexachlorado-dicadmate single crystal has been studied by means of a differential scanning calorimetry, Raman measurements and electrical impedance spectroscopy. Differential scanning calorimetry and Raman measurements performed with temperature to disclose a transition at 420 K and prove a key role of the cations in the mechanisms of disorder found on single crystal. The Z' and Z '' versus frequency plots are well fitted to an equivalent circuit model. The Kohlrausch-Williams-Watts function and the coupling model are used for analyzing electric modulus at various temperatures. The temperature dependence of the electrical conductivity in the different phases follows the Arrhenius law. The frequency dependence of sigma (omega) follows the Jonscher's universal dynamic law with the relation sigma(omega) = sigma(0) + A omega(n), where omega is the frequency of the AC field, and n is the exponent. The imaginary part of the permittivity constant is analyzed with the Cole-Cole formalism. In the temperature range 377-433 K, the activation energy obtained from the conductivity and the modulus spectra suggests that the ion transport is probably due to a hopping mechanism. (C) 2010 Elsevier B.V. All rights reserved.