Influence of cations vacancies on the K and LIII Zn edges of spinel-related compounds.
Compounds having oxygen vacancies exhibit particular physico-chemical properties. For example, in the ease of the perovskite type cubic system, disordered oxygen vacancies are intimately linked to ionic conductivity (Mori et al, 1994). Here we conduct a fundamental research study dedicated to spinel related compounds in order to discuss the information which can be extracted from the XANES part of the absorption spectra. In order to achieve this goal, we first recall the structural characteristics of the ZnAI204 reference compound and the structural parameters derived from the numerical simulations of the EXAFS modulations collected at the Zn K edge on a set of original materials coming from soft chemistry (Bazin et al, 1998). Then, we will discuss the XANES data obtained at the Zn K and Lm edges as well as the numerical simulations performed us ing the FeFF program and corresponding to several structural hypothesis (essentially influence of Zn or O vacancies).