Large magnetic polarization of Ti⁴⁺ ions in FeTiO₃

Nominal valence states of Ti ions in FeTiO₃ are generally considered to be Ti⁴⁺. However, due to the close energy levels between Fe²⁺ and Ti⁴⁺ states, there are some possibilities of intervalence charge transfer from Fe²⁺ to Ti⁴⁺. In order to clarify the real electronic structures of Ti ions in FeTiO₃, we performed resonant photoemission spectroscopy (RPES) and X-ray magnetic circular dichroism (XMCD) across the Ti 2p→3d excitation. The RPES spectra clearly indicated the partial density of states derived from the Ti 3d states on the valence band. The Ti 3d states appearing at the top of the valence bands were overlapped with the Fe 3d states. Moreover, the XMCD spectra at Ti L_2,3 edges suggested large magnetic polarization of Ti ions in FeTiO₃ in spite of nonmagnetic natures of Ti⁴⁺ ions in common sense. The Ti ions in FeTiO₃ seemed to have some 3d electron densities caused by the electron transfer from the Fe 3d t_2g↓ states.