Open AccessTHERMAL AND ELECTRICAL BEHAVIOUR OF THE SUPERPROTONIC CONDUCTOR PHASE IN Rb2(HSeO4)1.5(H2AsO4)0.5
Author(s) -
N. Nouiri,
K. Jaouadi,
Tahar Mhiri
Publication year - 2014
Publication title -
journal of advances in chemistry
Language(s) - English
Resource type - Journals
ISSN - 2321-807X
DOI - 10.24297/jac.v10i7.6810
Subject(s) - phase transition , dielectric spectroscopy , raman spectroscopy , materials science , analytical chemistry (journal) , phase (matter) , differential thermal analysis , electrical impedance , electrical resistivity and conductivity , endothermic process , chemistry , thermodynamics , diffraction , electrochemistry , optics , physics , electrical engineering , organic chemistry , chromatography , adsorption , engineering , electrode
Crystals of a new compound with a superprotonic phase transition Rb2(HSeO4)1.5(H2AsO4)0.5 (noted RbHSeAs), were synthesized by slow evaporation of an aqueous solution at room temperature. The differential scanning calorimetric analyses showed two endothermic peaks at 465 K and 566 K. The last peak corresponds to the decomposition of the material. The first transition was characterized by several techniques (impedance spectroscopy, complex modulus, Raman and X-ray diffraction powder depending on temperature). ac impedance measurements revealed that, upon heating, the compound undergoes at ~ 443 K a sharp increase in conductivity from a low temperature protonic phase to a superprotonic conductivity phase. The activation energies calculated from the modulus (Ef) and impedance (E) spectra respectively are approximately equal, suggesting that the transport properties in this material above and below the superprotonic phase transition (443 K) are probably due to an H+ protons hopping mechanism.