Multiple-scattering approach to Ti L2,3-edge XMCD analyses for Co doped TiO2

Abstract

We have measured Ti L2,3-edge X-ray magnetic circular dichroism (XMCD) spectra of Co doped anatase TiO2 (Co0.05Ti0.95O2), where nonzero XMCD spectra have been observed even at Ti L2,3-edge. In order to understand the reason why the XMCD signals are observed at Ti L2,3-edge, we have applied the relativistic multiple-scattering approach to the analyses of the observed XMCD spectra. The results show that the Ti L2,3-edge XMCD spectra are dominated by the spin-dependent exchange scatterings on the spin-polarized Co sites. We find a good agreement with the observed L3 XMCD spectra. The calculated XMCD spectra are rather sensitive to the spin moment on the X-ray absorbing Ti. We conclude that the spin moment on Ti site is very small and antiparallel to that on Co. The calculated results also show that the observed Ti L2,3-edge XMCD signals arise from the Ti atoms within about 4 Å from spin-polarized Co atoms.