EXAFS, XRD and RMC studies of an Amorphous Ga$_{50}$Se$_{50}$ Alloy Produced by Mechanical Alloying

摘要

The local atomic order of an amorphous Ga$_{50}$Se$_{50}$ alloy produced byMechanical Alloying (MA) was studied by the Extended X-ray Absorption FineStructure (EXAFS) and X-ray Diffraction (XRD) techniques and by Reverse MonteCarlo (RMC) simulations of its total x-ray structure factor. The coordinationnumbers and interatomic distances for the first neighbors were determined bymeans of EXAFS analysis and RMC simulations. The RMC simulations also furnishedthe partial pair distribution functions $G^{\text{RMC}}_{\text{Ga-Ga}}(r)$,$G^{\text{RMC}}_{\text{Ga-Se}}(r)$ and $G^{\text{RMC}}_{\text{Se-Se}}(r)$. Theresults obtained indicated that there are important differences among the localstructure of the amorphous Ga$_{50}$Se$_{50}$ alloy produced by MA and those ofthe corresponding crystals, since there are Se-Se pairs in the firstcoordination shell of the amorphous alloy that are forbidden in theGa$_{50}$Se$_{50}$ crystals.