The influence of the concentration of Sb ions onto the local crystal and electronic structures of CuCr2−xSbxS4 (x = 0.3, 0.4, 0.5) studied by XANES and EXAFS measurements and LAPW numerical calculations

The X-ray absorption K-edges of sulfur in CuCr2−xSbxS4 (x = 0.3, 0.4, 0.5) have been measured and compared to linearized augmented plain wave (LAPW) numerical calculations. The near edge region is generated by magnetically polarized and hybridized S 2p energy levels and shows small change with increased Sb content, which can be attributed to the movement of Cr 3d spin-down states up on the energy scale. The LAPW result confirms this effect. Moreover, the calculations show that the antimony in those spinels is rather in +3 than in +5 valence state. The calculated magnetic moment on Cr equals to 2.72μB. In EXAFS, there is no visible change between x = 0.3 and 0.5 spectra, which indicates that the local structure does not change significantly.