Étude des propriétés de conduction électrique des phosphates condensés mixtes éléments monovalents-terres rares : LiDy(PO$_3$)$_4$, NaNd(PO$_3$)$_4$, AgLa(PO$_3$)$_4$, NH$_4$DyPO$_3$)$_4$

M. Férid; K. Horchani; A. Touai; A. Madani; H. Boussetta; M. Trabetsi-Ayedi

doi:doi:10.1051/jp4:20040025

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Volume 113 (January 2004)

J. Phys. IV France, 113 (2004) 115-118

Abstract

Free Access

Issue		J. Phys. IV France Volume 113, January 2004


Page(s)		115 - 118
DOI		https://doi.org/10.1051/jp4:20040025

J. Phys. IV France 113 (2004) 115
DOI: 10.1051/jp4:20040025

Étude des propriétés de conduction électrique des phosphates condensés mixtes éléments monovalents-terres rares : LiDy(PO ₃) ₄, NaNd(PO ₃) ₄, AgLa(PO ₃) ₄, NH ₄DyPO ₃) ₄

M. Férid¹, K. Horchani¹, A. Touai², A. Madani², H. Boussetta² and M. Trabetsi-Ayedi³

¹ Laboratoire des Procédés Chimiques, Institut National de Recherche Scientifique et Technique, BP. 95, 2050 Hammam-Lif, Tunisie
² Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte, 7021 Zarzouna, Tunisie
³ Laboratoire de Physique-Chimie Minérale, Faculté des Sciences de Bizerte, 7021 Zarzouna, Tunisie

Abstract
Single crystals of LiDy(PO ₃) ₄, NaNd(PO ₃) ₄, NH ₄Dy(PO ₃) ₄ and AgLa(PO ₃) ₄ polyphosphates have been grown using the flux method. A mixture of monovalent carbonate (M ₂CO ₃), rare earth oxide (Ln ₂O ₃) and phosphoric acid (H ₃PO ₄ 85%) was heated at 285°C during a week. Single crystals were obtained and characterized by X-ray diffraction, infrared and Raman spectroscopy. Their investigation was carried out by thermal analysis (ATG/ATD). Their electric conductivity was measured by impedance spectroscopy. The conductivity, $\sigma$ , vary between $1{,}5\times10^{-8}~\Omega^{-1}$ .cm ^-1 at 300 °C and $2\times10^{-5}~\Omega^{-1}$ .cm ^-1 at 500 °C. The activation energies increase from 0,31 for NH ₄Dy(PO ₃) ₄ to 1,26 eV for NaNd(PO ₃) ₄. The basic structural units of these phosphates are ribbons (PO ₃) $_{\rm n}$ formed by corner-sharing of PO ₄ tetrahedra with variable geometry, which are unfavourable to the ionic conduction. The ionic transport was mainly assured by M ⁺ ions; moreover, the hydrogen bond established in the structure of NH ₄Dy(PO ₃) ₄ and the proton exchange allow to explain the relatively high conductivity of this phosphate. The results are discussed and correlated to the structural properties of these phosphates.

Étude des propriétés de conduction électrique des phosphates condensés mixtes éléments monovalents-terres rares : LiDy(PO 3) 4, NaNd(PO 3) 4, AgLa(PO 3) 4, NH 4DyPO 3) 4

Étude des propriétés de conduction électrique des phosphates condensés mixtes éléments monovalents-terres rares : LiDy(PO ₃) ₄, NaNd(PO ₃) ₄, AgLa(PO ₃) ₄, NH ₄DyPO ₃) ₄