Electrical conduction mechanism and dielectric properties of the [C13H16N2]5(BiCl6)3Cl hybrid compound

In this research paper, the [C13H16N2]5(BiCl6)3Cl compound was synthesized, by slow evaporation, at room temperature. It was analyzed by X-ray diffraction, thermal analysis and impedance spectroscopy techniques. The phase transition at T = (400 ± 5)K was evidenced by DSC measurements and confirmed by the electrical study. The electrical measurements were performed in a wide interval of frequency (40–107 Hz) and temperature (300–440 K). The AC conductivity dependence on angular frequency was found to obey the Jonscher’s universal power law described by ({sigma }_{mathrm{AC}}left(omega ,{ m T} ight)={sigma }_{mathrm{DC}}({ m T})+B{left({ m T} ight) omega }^{s({ m T},omega )}). Besides, the AC electrical conduction in the prepared material was explained by two theoretical models related to a hopping transport mechanism: the non-overlapping small polaron tunneling (NSPT) model in phase I and (III) and the correlated barrier hopping (CBH) mechanism in phase (II). DC data were found to obey Arrhenius law with activation energies 133 meV and 1.85 eV in agreement with AC measurements and the frequency-dependent maxima ωmax of the imaginary part of modulus. The Nyquist plots were well fitted to an equivalent circuit model taking into account the contribution of grains and grain boundaries. Furthermore, dielectric permittivities were shown to be consistent with the Havriliak–Negami relaxation model.