Magnetic circular X-ray dichroism at pre-peak of Fe K-edge in ferrimagnetic Fe-oxides

Abstract

We propose a mechanism of the magnetic circular X-ray dichroism (MCXD) at the pre-peak of the Fe K -edge in Fe-oxides. It is found that the hybridization between the 3 d state and the 4 p state of Fe ions at tetrahedral sites through the ligand 2 p state is responsible for the weak electric-dipole absorption at the pre-peak while the spin-orbit interaction and the spin polarization in the 3 d state play a crucial role in MCXD. The important effects of the configuration interaction as well as of the core hole are discussed in connection with the asymmetric dispersion-type MCXD observed in rare-earth iron garnets and magnetites.