Copper Manganese Spinel Research Articles

Environnement tetraedrique de l'ion Cu 2+ et structure fine du seuil d'absorption K dans quelques chromites: application à l'étude d'oxydes à valence mixte

Copper zinc and copper manganese spinel chromites are studied using neutron diffraction. Cr 3+ ions in tetrahedral environments are observed in CuCr 2O 4 and Cu 0.25Zn 0.75Cr 2O 4. These results leads to a new interpretation of the optical spectra (drs). The measurement of X-ray absorption fine structure of copper in the near edge rayon (Xanes) have been obtained using the Lure synchrotron radiation sources (Orsay, France). The spectra of Cu 2+ in the tetrahedral environment of a quadratic or cubic matrix are characterized by the splitting of the main peak in the range 18–23 eV above the 1 s → 3 d transition. The X-ray absorption spectroscopy reveals the two oxidation states of copper in mixed oxides such as CuCrMnO 4. The copper(I) 1 s → 4 s transition is observed as a shoulder located at 10 eV on the slope of the main peak. A finer structure appears in the derivative spectrum.