XAFS STUDY OF INTERCHAIN AND INTRACHAIN ORDER IN SE1-XTEX GLASSES - NEAREST NEIGHBORS

XAFS measurements (LURE and NSLS) of Se1-xTex glasses have been carrie d out on both the Se and Te K edges at low and room temperatures. Usin g a multishell best-fit analysis procedure, we have reconstructed the Se and Te local environment: first-shell intrachain nearest neighbors (Se-Se-1, Se-Te-1, Te-Se-1, and Te-Te-1). We conclude that the intrach ain chemical order (preferential of Se-Te pairs) increases with Te con tent in the glasses. On the other hand, we suggest a random distributi on of Se and Te atoms between the chains. The thermal disorder dominat es for the first-shell pairs Se-Se-1, Se-Te-1 (Te-Se-1), and Te-Te-1 p airs. The obtained results provide insight on intrachain structure as well as on the structural and thermal disorder of mixed Se1-xTex glass es.