Local Dynamics in Metallic Liquids Studied by Inelastic Neutron Scattering

Local dynamics in liquid metals has been poorly understood when compared to their crystalline counterparts. For instance, the atomistic origin of the viscous behavior is not well elucidated, even though viscosity is one of the most basic properties for liquids. In this research, inelastic neutron scattering (INS) experiments were carried out on various metallic liquid droplets (including single, binary, and complex BMG forming liquids), using an electro-static levitator, at different temperatures at SNS. The dynamic structure function S(Q, E) and the Van Hove correlation function G(r,t) were then obtained. Compared with Molecular Dynamics (MD) simulation results, the local configuration change was analyzed based on distinct G(r,t) and proved as the elementary excitation in high temperature metallic liquids, thus controlling their shear viscosity. Also, self diffusion behaviors were analyzed based on self G(r,t). A comprehensive understanding of the local dynamics was made in various metallic liquids.