Structure analysis, morphological observations and electrical behavior of Co0·4Fe2·6O4 synthesized by surfactant-free solvothermal route - Le Mans Université Accéder directement au contenu
Article Dans Une Revue Solid State Sciences Année : 2022

Structure analysis, morphological observations and electrical behavior of Co0·4Fe2·6O4 synthesized by surfactant-free solvothermal route

Résumé

Cobalt nano-ferrite of formula Co0·4Fe2·6O4 was successfully prepared by a surfactant-free solvothermal reaction. Powder X-ray Diffraction (PXRD) revealed a cubic spinel structure. Transmission Electron Microscopy (TEM) observations confirmed the presence of agglomerated nanoparticles of two different sizes and shapes. 57Fe Mössbauer Spectrometry (MS) studies suggested a cationic redistribution between tetrahedral and octahedral sites in the spinel lattice. The low-frequency dependence of the dielectric properties is significantly affected by the presence of all polarization phenomena, in particular the interface polarization, on the basis of the phenomenological theory of the Koop model and the Maxwell-Wagner approach. At low frequencies, a linear negative correlation between the imaginary part of the permittivity and the frequency in the logarithm scale is observed. This is attributed to a dc-conductivity process. Furthermore, the electrical modulus analysis shows both Debye and non-Debye dielectric relaxations. The complex impedance plots were analyzed using the equivalent circuit model; grain and grain boundaries effects coexist. In the conductivity spectra, three regions were detected. A single power law and a double power law were separately applied to resolve the grains and grain boundaries effects. This unusual conductivity behavior can be explained by the modification in microstructure as well as the variation in charge carrier mobility. All results were interpreted in terms of microstructure properties and correlated with the cationic distribution within the spinel structure. The close values of activation energies obtained from the impedance, modulus and ac-conductivity in different temperature regions confirmed that the transport is probably due to a hopping mechanism dominated by smaller amount of oxygen vacancies.

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Chimie
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Dates et versions

hal-04096192 , version 1 (12-05-2023)

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Amira Chérif, Mohamed Saidani, Ichraf Chérif, Jean Marc Greneche, Najeh Thabet Mliki. Structure analysis, morphological observations and electrical behavior of Co0·4Fe2·6O4 synthesized by surfactant-free solvothermal route. Solid State Sciences, 2022, 134, pp.107028. ⟨10.1016/j.solidstatesciences.2022.107028⟩. ⟨hal-04096192⟩
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