title: Experimental evidence for a dynamical crossover in liquid aluminium.
abstract: The temperature dependence of the dynamic structure factor at next-neighbour distances has been investigated for liquid aluminium. This correlation function is a sensitive parameter for changes in the local environment and its Fourier transform was measured in a coherent inelastic neutron scattering experiment. The zero frequency amplitude decreases in a nonlinear way and indicates a change in dynamics around 1.4 ∙ Tmelting. From that amplitude a generalized viscosity can be derived which is a measure of local stress correlations on next-neighbour distances. The derived generalized longitudinal viscosity shows a changing slope at the same temperature range. At this temperature the freezing out of degrees of freedom for structural relaxation upon cooling sets in which can be understood as a precursor towards the solid state. That crossover in dynamics of liquid aluminium shows the same signatures as previously observed in liquid rubidium and lead, indicating an universal character.
authors.affiliation: ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
authors.forename: F
authors.initials: F
authors.lastname: Demmel
authors.forename: A
authors.initials: A
authors.lastname: Fraile
authors.forename: D
authors.initials: D
authors.lastname: Szubrin
authors.forename: W-C
authors.initials: WC
authors.lastname: Pilgrim
authors.forename: C
authors.initials: C
authors.lastname: Morkel