XMCD Investigation of Spin Disorder in -Fe2O3 Nanoparticles at the Fe L2,3 Edges.
Résumé
We use XMCD at the L2,3 edges of iron to analyze the site-specific magnetic contributions of ions in nanoparticles of maghemite, -Fe2O3. Maghemite is the oxidized form of magnetite Fe3O4.We report results of the study of the magnetic order on tetrahedral and octahedral magnetic sublattices in -Fe2O3 nanoparticles as a function of the applied magnetic field. Magnetic contributions of Fe3+ Oh and Fe3+ Td are determined using the Ligand Field Multiplet theory. It is found that when the external field decreases, the magnetic contribution of Fe3+ ions on octahedral sites is significantly reduced by comparison to the contribution of Fe3+ ions on tetrahedral ones. This shows that a higher degree of canting exits on octahedral sites.