Thermal stability and electrical properties of XFe2O4 (X = Co,Cu,Fe,Mg,Mn,Ni) high-entropy spinel ferrites prepared by reactive flash sintering
This study investigates the high-temperature stability and phase composition of two high-entropy oxides (HEOs), (Mn0.2Co0.2Ni0.2Cu0.2Fe0.2)Fe2O4 and (Mn0.2Co0.2Ni0.2Cu0.2Mg0.2)Fe2O4, prepared as single-phase samples using the reactive flash sintering technique. Results show that the annealing temper...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/398688 |
| Acceso en línea: | http://hdl.handle.net/10261/398688 https://api.elsevier.com/content/abstract/scopus_id/105008516205 |
| Access Level: | acceso abierto |
| Palabra clave: | Spinel-type ferrite High-entropy oxides Impedance spectroscopy Reactive flash sintering Thermal stability |
| Sumario: | This study investigates the high-temperature stability and phase composition of two high-entropy oxides (HEOs), (Mn0.2Co0.2Ni0.2Cu0.2Fe0.2)Fe2O4 and (Mn0.2Co0.2Ni0.2Cu0.2Mg0.2)Fe2O4, prepared as single-phase samples using the reactive flash sintering technique. Results show that the annealing temperature in a nitrogen atmosphere has a significant impact on the stability of the compounds. The destabilization of the spinel structure occurs in a two-step process: spinel HEO spinel HEO + Fe2O3 spinel HEO + Cu based-oxide. This sequence is inferred from in-situ XRD experiments and calorimetric analysis, and confirmed by TEM observations. Impedance spectroscopy analysis revealed a complex, thermally activated electrical response comprising bulk and grain boundary contributions. AC conductivity follows Jonscher’s universal power law, with a temperature dependence of the parameter consistent with overlapping large polaron tunneling. These findings provide insight into charge transport and relaxation processes in the prepared HEOs, improving their understanding for potential electrical applications. |
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