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Percolation Model of the Temperature Dependence of Resistivity in Pr0.67A0.33MnO3 (A = Ba or Sr) Manganites |
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| Authors: | S. Hcini S. Khadhraoui S. Zemni A. Triki H. Rahmouni M. Boudard M. Oumezzine |
| Affiliation: | 1. Laboratoire de Physico-chimie des Matériaux, Département de Physique, Faculté des Sciences de Monastir, Université de Monastir, 5019, Monastir, Tunisie 2. Laboratoire des Matériaux Composites, Céramiques et Polymères, Faculté des Sciences de Sfax, Université de Sfax, Sfax, Tunisie 3. Laboratoire de Physique des Matériaux et Nanomatériaux Appliqués à l’Environnement, Faculté des Sciences de Gabès, Département de Physique, Université de Gabès, 6079, Gabès, Tunisie 4. Laboratoire des Matériaux et du Génie Physique, Grenoble INP, CNRS (UMR 5628), MINATEC, 3 parvis Louis Néel, BP 257, 38016, Grenoble Cedex 1, France |
| Abstract: | The analyses of resistivity experimental results of Pr0.67Ba0.33MnO3 (PBMO) and Pr0.67Sr0.33MnO3 (PSMO) manganites are presented. The electrical resistivity curves are fitted with the phenomenological percolation model, which is based on the phase segregation of ferromagnetic–metallic (FMM) clusters and paramagnetic–insulating (PMI) regions. The estimated results are in good agreement with experimental data. We found that the transition to the metallic state occurs if the volume fraction of the ferromagnetic phase reaches a percolation threshold, suggesting that the percolation of ferromagnetic (FM) domains is responsible for the observed metal–insulator (M–I) transition. According to the percolation model, we found that the energy gap of the quasi-particles in the phase separated FM and PM states is significantly smaller for PBMO than that for PSMO confirming that PSMO is more conductive than PBMO. We also found that the volume fraction of the ferromagnetic phase has the same physical meaning as the reduced magnetization. |
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