Exchange bias effects in Fe nanoparticles embedded in an antiferromagnetic Cr2O3 matrix
Résumé
Powders consisting of ferromagnetic (FM) Fe nanoparticles, of about 7 nm in size, embedded in an antiferromagnetic (AFM) Cr2O3 matrix have been obtained by high-temperature reduction under a hydrogen atmosphere of a mixed Cr-Fe oxide. This FM-AFM system exhibits exchange bias effects, i.e. a loop shift (HE) and coercivity enhancement (ΔHC), when field-cooled through the N'eel temperature, TN, of Cr2O3. The exchange bias properties were measured as a function of temperature. HE and ΔHC are found to vanish at about TN(Cr2O3), indicating a good quality AFM matrix. Hence, high-temperature reduction of mixed oxides is demonstrated to be a suitable technique to develop new types of FM-AFM exchange-biased nanoparticles, from which novel applications of this phenomenon may be developed.
Domaines
Matériaux| Origine | Fichiers produits par l'(les) auteur(s) |
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