Absence of charge ordering below the Verwey transition temperature in magnetite - art. no. 054110

The electronic state of Fe3O4 below the Verwey transition has been studied by x-ray resonant scattering at the iron K edge of the forbidden (0 0 2) an d (0 0 6) reflections. These reflections are permitted by the anisotropy of the iron anomalous scattering factor. The energy and the azimuthal angle d ependence of the intensity of these reflections do not change above and bel ow the transition temperature. Moreover, the spectrum at low temperature do es not change upon orientation of the crystal c axis. The results clearly s how that no charge ordering of Fe3+ and Fe2+ occurs in the insulating phase of magnetite. We also discuss the possible charge ordering models, assumin g the Cc symmetry and the Anderson condition. Only two models, out of ten a nalyzed, do not give any isotropic contribution to the forbidden reflection s and could support a charge disproportionation. Nevertheless, it should be at most 25%.