Influence of the short-range order on the atomic dynamics in metallic melts

Neutron scattering and synchrotron x-ray diffraction experiments were carried to study the diffusion mechanism in metallic liquids. In the studied systems with weak chemical interactions, a considerable impact of the topological short-range order on the atomic diffusion is found. Here, concentration dependence of the diffusivity can be fully understood according to predictions of the mode-coupling theory (MCT) on hard-sphere mixtures. In contrast, also contributions from chemical short-range order can cause an extensive influence on the melt dynamics, which explains the changes of the atomic diffusivity even upon minor additions of another component.