Electronic structure of halogen doped CuCr_(2)Se_(4)

摘要

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 CuCr_(2)Se_(4) via halogen doping of the Se anion site in CuCr_(2)Se_(4-x)Y_(x) (Y(velence)Cl and Br). Long range magnetic order is observed above room temperature for all samples. The Cr L_(2,3) XAS spectra show a prevalent 3+ valence for the Cr ions independent of doping concentration and doping agent. The Cu L_(2,3) 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.