Structural properties of liquid Au–Si and Au–Ge alloys with deep eutectic region

Au–Si and Au–Ge alloys have a deep eutectic region around 19 at.% Si and 28 at.% Ge, respectively. The metallic glass was prepared by quenching around 25 at.% Si near the eutectic composition for the Au–Si alloys 2] which has stimulated many researchers to study on the structural properties of such liquid alloys. However their results were different from each other, which seems due to the experimental difficulties from heavy absorption of both X-ray and neutron beams by Au atom in diffraction experiments. X-ray diffraction measurements have been carried out for liquid Au–Si and Au–Ge alloys around the eutectic region by the transmission method using high-energy X-rays to investigate the atomic arrangements in the liquid state. From the temperature dependence of the observed structure factors, the partial pair correlation and the detailed atomic arrangements will be discussed by Reverse Monte Carlo analysis. The produced atomic arrangements around the eutectic region suggest a substitutional structure and also an increase in liquid density with decreasing temperature.