6533b7dcfe1ef96bd1271cbc

RESEARCH PRODUCT

XAFS study of interchain and intrachain order inSe1−xTexglasses: Nearest neighbors

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XAFS measurements (LURE and NSLS) of ${\mathrm{Se}}_{1\ensuremath{-}x}{\mathrm{Te}}_{x}$ glasses have been carried out on both the Se and Te $K$ edges at low and room temperatures. Using a multishell best-fit analysis procedure, we have reconstructed the Se and Te local environment: first-shell intrachain nearest neighbors $(\mathrm{Se}\ensuremath{-}{\mathrm{Se}}_{1}, \mathrm{Se}\ensuremath{-}{\mathrm{Te}}_{1}, \mathrm{Te}\ensuremath{-}{\mathrm{Se}}_{1},$ and $\mathrm{Te}\ensuremath{-}{\mathrm{Te}}_{1}).$ We conclude that the intrachain chemical order (preferential of Se-Te pairs) increases with Te content in the glasses. On the other hand, we suggest a random distribution of Se and Te atoms between the chains. The thermal disorder dominates for the first-shell pairs $\mathrm{Se}\ensuremath{-}{\mathrm{Se}}_{1}, \mathrm{Se}\ensuremath{-}{\mathrm{Te}}_{1} (\mathrm{Te}\ensuremath{-}{\mathrm{Se}}_{1}),$ and $\mathrm{Te}\ensuremath{-}{\mathrm{Te}}_{1}$ pairs. The obtained results provide insight on intrachain structure as well as on the structural and thermal disorder of mixed ${\mathrm{Se}}_{1\ensuremath{-}x}{\mathrm{Te}}_{x}$ glasses.