Electronic structure and x-ray magnetic circular dichroism in Fe3O4 and Mn-, Co-, or Ni-substituted Fe3O4

The electronic structure of charge-ordered magnetite (Fe3O4) below the Verwey transition and Mn-, Co-, or Ni-substituted Fe3O4 are investigated theoretically from first principles, using the fully relativistic Dirac linear muffin-tin orbital band-structure method. The electronic structure is obtained with the local spin-density approximation (LSDA), as well as with the so-called LSDA+U approach, for which the charge ordering is found to be a stable solution in contrast to a metallic state given by the LSDA. The x-ray absorption spectra as well as the x-ray magnetic circular dichroism spectra at the K, L-2,L-3, and M-2,M-3 edges for transition metal sites are calculated. A good agreement between theory and experiment is obtained.