Electronic structure of halogen doped CuCr2Se4.

We have employed element and chemically sensitive x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) in order to address a long standing controversy regarding the electronic and magnetic states of CuCr2Se4 via halogen doping of the Se anion site in CuCr2Se4-xYx (Y=Cl and Br). Long range magnetic order is observed above room temperature for all samples. The Cr L2,3 XAS spectra show a prevalent 3+ valence for the Cr ions independent of doping concentration and doping agent. The Cu L2,3 XAS spectra show a combination of 1+ and 2+ valence states for all samples. XMCD spectra indicate the presence of a magnetic moment associated with the Cu ions that is aligned antiparallel to the Cr moment. [ABSTRACT FROM AUTHOR]