We have implemented the calculation of the x-ray-absorption cross section for left- and right-circularly polarized x-ray beams within the local-density approximation by means of our all-electron full-relativistic and spin-polarized full-potential linear muffin-tin orbital method. We show that the $L_{2,3}$ circular magnetic x-ray dichroism of Fe, ${\mathrm{Fe}}_3\mathrm{N},$ and ${\mathrm{Fe}}_4\mathrm{N}$ compounds scales to a single curve when divided by the local magnetic moment. Sum rules determine the spin and orbital magnetic moment of iron atoms in these ordered iron nitrides.

• Received 18 December 1997

DOI:https://doi.org/10.1103/PhysRevB.57.9502