L-edge inner shell spectroscopy of nanostructured Fe3O4

Abstract We have measured magnetic circular dichroism at the Fe L edge in samples of colloidal Fe 3 O 4 and in Fe 3 O 4 powder. The results for the colloid can be interpreted in terms of the model presented by Sette et al. for the dichroism of bulk Fe 3 O 4 . We notice a shift in the position of the Fe L 3 line in the colloid with regard to the powder, which is however in the opposite direction as expected for a cluster. We observe a new structure in the dichroism of the colloid spectrum that could be cluster-specific, in spite of the fact that, for the cluster size of our colloids, the fraction of atoms at the surface of the cluster is not large.