New Composites of ZnO-P2O5/Ni Having PTC Transitions and High Seebeck Coefficients - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Non-Crystalline Solids Année : 2012

New Composites of ZnO-P2O5/Ni Having PTC Transitions and High Seebeck Coefficients

, , (1) , , (2)
1
2
A. Maaroufi
  • Fonction : Auteur
Omar Oabi
  • Fonction : Auteur
Bruno Lucas
A. El Amrani
  • Fonction : Auteur

Résumé

In this article, we report the electrical conductivity (σ) and Seebeck coefficient (S) of ZnO-P2O5 matrix filled with conductive powder of nickel (Ni). The variation of σ versus volume fraction of Ni showed a non-conducting to conducting phase transition at percolation threshold (28 vol. %). The change of S from high positive to negative values exhibits that this transition is accompanied by the passing of carrier charge from p to n type. On the other hand, the measurements of σ and S as function of temperature, above the percolation threshold, showed a positive temperature coefficient (PTC) phase transition at Tc ≥ 400 K, linked with a high S = − 5000 μV/K, giving highest power factor PF = σ.S 2≈ 2.10− 4 W m− 1 K− 2. The temperature dependence of the volume expansion enabled to confirm that this transition is associated to the thermal volume variation in matrix. However, the temperature dependence of σ below the percolation threshold showed two different mechanisms: thermally activated hopping behavior at high temperatures and Mott's variable range hopping (VRH) at low temperatures.
Fichier non déposé

Dates et versions

hal-00934895 , version 1 (22-01-2014)

Identifiants

Citer

A. Maaroufi, Omar Oabi, Bruno Lucas, A. El Amrani, Sébastien Degot. New Composites of ZnO-P2O5/Ni Having PTC Transitions and High Seebeck Coefficients. Journal of Non-Crystalline Solids, 2012, 358 (23), pp.3312-3317. ⟨10.1016/j.jnoncrysol.2012.09.003⟩. ⟨hal-00934895⟩
53 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook Twitter LinkedIn More