Extended x-ray absorption fine structure, x-ray diffraction and reverse Monte Carlo studies of an amorphousGa50Se50 alloy produced by mechanical alloying

Abstract

The local atomic order of an amorphousGa50Se50 alloy produced by mechanical alloying (MA) was studied by the extended x-ray absorption finestructure (EXAFS) and x-ray diffraction (XRD) techniques and by reverse Monte Carlo (RMC)simulations of its total x-ray structure factor. The coordination numbers and interatomicdistances for the first neighbours were determined by means of EXAFS analysis and RMCsimulations. The RMC simulations also furnished the partial pair distribution functionsGGa−GaRMC(r),GGa−SeRMC(r) andGSe−SeRMC(r). Theresults obtained indicated that there are important differences among the local structure of the amorphousGa50Se50 alloy produced by MA and those of the corresponding crystals, since there are Se–Se pairsin the first coordination shell of the amorphous alloy that are forbidden in theGa50Se50 crystals.