Diffuse scattering and chemical short range order in binary metallic glasses

X-ray and neutron scattering from binary metallic glasses is discussed in the context of the Bhatia-Thornton equations for the structure factor. For neutrons a generalised form of the Bhatia-Thornton equation must be used when there are different isotopes present. By making a distinction between correlated and uncorrelated scattering centres an expression can be derived which shows clearly the different contributions to the total scattered intensity. Information about the relative visibility of the alloy components can be obtained from this expression and a figure of merit or degree of contrast between the species defined, which is helpful in understanding results of experiments performed to date.