Laboratoire Of Physique Appliquee

Sfax, Tunisia

Laboratoire Of Physique Appliquee

Sfax, Tunisia
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Sdiri N.,Laboratoire Of Physique Appliquee | Boukhachem A.,Tunis el Manar University | Dhahri E.,Laboratoire Of Physique Appliquee
Ceramics - Silikaty | Year: 2012

Using spectroscopic ellipsometry, we have studied the optical properties of doped manganites at the paramagnetic state in polycrystalline La 0.7Ca 0.3-xK xMnO 3 samples for (x = 0.00, 0.05 and 0.10) in the energy range of 3.2-5.5 eV at room temperature. The surface morphology of the samples was obtained by using atomic force microscopy (AFM). Refractive indices, extinction coefficients, the transmission ellipsometric parameters ω and δ are investigated at different wavelengths. The study of the optical conductivity ? reveals that optical behaviour and the activated transport in the paramagnetic state of these materials are consistent with Jahn-Teller small polaron. In addition, the spectrum of the complex dielectric constant σ reveals peaks for all samples, the results may be explained by the presence of space charges from the strongly dipole-allowed O(2p)?Mn(3d) transition.


Trabelsi I.,Laboratoire Of Physique Appliquee | Dammak M.,Laboratoire Of Physique Appliquee | Maalej R.,Laboratoire Of Physique Appliquee | Kamoun M.,Laboratoire Of Physique Appliquee
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

Crystal-field energy levels of Er3+ ions doped in KYb(WO4)2, KY(WO4)2 and KLu(WO4)2 laser crystals were fitted to the parameters of semi-empirical Hamiltonian including J-mixing. A simulation of the energy level scheme is carried out. The crystal-field effect is introduced through the 14 non-zero crystal-field parameters allowed by C2 symmetry site occupied by the rare earth. Very satisfactory correlations were obtained between 58, 64 and 15 calculated and experimental Stark energy levels, with an r.m.s. of 8.7 cm-1, 9.3 cm-1 and 2.6 cm-1 for Er3+ ions doped in KYb(WO4)2, KY(WO4)2 and KLu(WO4)2 respectively. These results are compared with those reported for other rare earth ions in the same hosts and with Er3+ ions in KGd(WO4)2 crystal. Furthermore, based on the extended electrostatic point charge model, interesting results are obtained for Yb3+ ions doped KYb(WO4)2, KY(WO4)2, KLu(WO4)2 and KGd(WO4)2 crystals. The concordance between the crystal-field strength parameters indicates the consistence of our analysis. A general trend is then proposed for the rare earth ions in the KRE(WO4)2 double tungstates. © 2010 Elsevier B.V. All rights reserved.


Trabelsi I.,Laboratoire Of Physique Appliquee | Maalej R.,Laboratoire Of Physique Appliquee | Dammak M.,Laboratoire Of Physique Appliquee | Lupei A.,National Institute for Laser, Plasma and Radiation Physics | Kamoun M.,Laboratoire Of Physique Appliquee
Journal of Luminescence | Year: 2010

A crystal field investigation of Er3+-doped Sc2O3 transparent ceramics is presented. The established energy level diagram is analyzed with crystal-field Hamiltonian of C2 symmetry including J-mixing effect. Very satisfactory correlations were obtained between 53 calculated and experimental Stark energy levels, with an rms of 7.7 cm-1. These results are compared with those reported for other rare earth ions in the same host and with Er3+ ions in other sesquioxides. The concordance between the crystal-field strength parameters indicates the consistence of our analysis. Furthermore, based on the extended electrostatic point charge model, a theoretical trend is proposed for rare earth ions in Sc2O3 in comparison with Y2O3. Based on this trend, very satisfactory results are obtained for Yb3+ ion in Sc2O3. © 2010 Elsevier B.V. All rights reserved.


Touati M.E.M.,Tunis el Manar University | Elleuch S.,Laboratoire Of Physique Appliquee | Boughzala H.,Tunis el Manar University
Acta Crystallographica Section E: Crystallographic Communications | Year: 2015

A new organic-inorganic hybrid material, {(C7H10NO)[BiI4]·2H2O} n , has been synthesized by slow evaporation of an aqueous solution at room temperature. The anionic sublattice of the crystal is built up by [BiI6] octahedra sharing edges. The resulting zigzag chains extend along the a-axis direction and are arranged in a distorted hexagonal rod packing. The p-anisidinium cations and the water molecules are located in the voids of the anionic sublattice. The cations are linked to each other through N - H⋯O hydrogen bonds with the water molecules, and also through weaker N - H⋯I interactions to the anionic inorganic layers.


PubMed | Tunis el Manar University and Laboratoire Of Physique Appliquee
Type: Journal Article | Journal: Acta crystallographica. Section E, Crystallographic communications | Year: 2015

A new organic-inorganic hybrid material, {(C7H10NO)[BiI4]2H2O} n , has been synthesized by slow evaporation of an aqueous solution at room temperature. The anionic sublattice of the crystal is built up by [BiI6] octa-hedra sharing edges. The resulting zigzag chains extend along the a-axis direction and are arranged in a distorted hexagonal rod packing. The p-anisidinium cations and the water mol-ecules are located in the voids of the anionic sublattice. The cations are linked to each other through N-HO hydrogen bonds with the water mol-ecules, and also through weaker N-HI inter-actions to the anionic inorganic layers.

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