Reference : Optical and AC conductivity studies on Li 2-x Rb x MoO 4 (x = 0, 0.5, 1) compounds
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/233561
Optical and AC conductivity studies on Li 2-x Rb x MoO 4 (x = 0, 0.5, 1) compounds
English
Ben Nasr, Wafa [Laboratory of Spectroscopic and Optical Characterization of Materials, Faculty of Sciences, University of Sfax, BP1171, Sfax, 3018, Tunisia]
Mahmoud, Abdelfattah mailto [Université de Liège - ULiège > Département de chimie (sciences) > LCIS - GreenMAT >]
Boschini, Frédéric mailto [Université de Liège - ULiège > > Plateforme APTIS >]
Ben Rhaiem, Abdallah [Laboratory of Spectroscopic and Optical Characterization of Materials, Faculty of Sciences, University of Sfax, BP1171, Sfax, 3018, Tunisia]
26-Feb-2019
Journal of Alloys and Compounds
Elsevier Ltd
788
522-532
Yes (verified by ORBi)
International
09258388
[en] Ac conductivity ; DRX ; Equivalent circuit ; OLPT model ; UV– visible
[en] In this work, we are interested in the new compounds Li 1.5 Rb 0.5 MoO 4 preparation by the solid state method. Also, we present a comparative study with LiRbMoO 4 and Li 2 MoO 4 . The X-ray powder diffraction indicates that these compounds crystallize at room temperature in the monoclinic, orthorhombic and trigonal systems with the P2 1 , Pcab and R-3 space groups, respectively. The shapes of the grains for these ceramics were observed by means of scanning electron microscopy (SEM) images. The Tauc model was used to determine the optical gap energy (4, 4.3 and 3.9 ev) and the urbach energies (1.51, 0.35 and 1.14 ev) of our compounds. The electric and dielectric proprieties of Li 1.5 Rb 0.5 MoO 4 have been studied. We carried out complex impedance spectroscopy in the frequency range 200 Hz-5 MHz at different temperatures (575–723 K). The complex impedance diagram showed a single semicircle, implying that the response originates corresponding to the grains. As a result, an electrical equivalent circuit has been proposed. The spectra follow the Arrhenius law with two energies of activation 1.58 eV for impedance measurements and 1.25 eV for that of modulus. The alternative current (AC) electrical conduction of the three compounds is governed by the overlapping large polaron tunneling (OLPT). © 2019
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/233561
10.1016/j.jallcom.2019.02.265

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