Synthesis, crystal structure, thermal analysis, dielectric properties and electrical conduction mechanisms of the new mixed solid solution of thallium rubidium sulfate selenate tellurate.

Author(s) Elferjani, A.; Garcia-Granda, S.; Dammak, M.
Journal Journal of Alloys and Compounds
Date Published 06/2018
Abstract The new mixed compound Tl1.90Rb0.10(SO4)0.92(SeO4)0.08Te(OH)6 (TlRbSSeTe) has been synthesized in order to determine the temperature transitions and to specify the electrical properties as well as the conduction mechanism. It is obtained by slow evaporation at room temperature and prove to crystallize in the monoclinic system with P21/c space group using X-ray diffractometer data. The basic property of these atomic arrangements is the coexistence of three different anions (SO42−, SeO42− and TeO66− groups) in the unit cell, related by O−H…O hydrogen bonds building up the crystal. Thermal analysis (DSC, DTA and TG) of the title compound confirms the presence of the phase transitions and the temperature of the decomposition of the studied salt. In order to characterize the phase transitions, Raman spectra have been recorded at various temperatures in the wavenumber range from 50–1200 cm−1. Detailed dielectric and electrical properties of the material have been analyzed as a function of frequency (100 Hz–10 MHz) and temperature (383–518 K). Besides, the analysis of Nyquist plots were well fitted to an equivalent circuit consisting of a series of combination of grains and grain boundary elements. The variation of the DC and AC conductivity confirms all the transitions of our sample. Furthermore, The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law (developed). The alternative current (AC) electrical conduction in TlRbSSeTe material is accounted for in terms of two processes that can be assigned to a hopping transport mechanism. These processes are the correlated barrier hopping (CBH) model in some regions, as well as the non-overlapping small polaron tunneling (NSPT) model in the other regions. The conduction mechanism for each phase is determined with the help of Elliot's theory.
DOI 10.1016/j.jallcom.2018.03.211
ISSN 0925-8388
Citation Journal of Alloys and Compounds. 2018;749:448464.

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