Dresden 2006 – scientific programme

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MM: Metall- und Materialphysik

MM 21: Amorphous and Liquid Materials II

MM 21.2: Talk

Tuesday, March 28, 2006, 16:45–17:00, IFW D

Inelastic Neutron Scattering on AlNi melts — •Sebastian Stüber, Suresh Mavila Chathoth, and Andreas Meyer — Physik Department E13, TU München

We report on inelastic neutron scattering (INS) measurements on Al₄Ni melts, comparing an alloy with natural Ni isotopic composition to a ⁵⁸Ni enriched sample. The experiments were performed at the new time-of-flight instrument of the neutron source FRM-II in Garching, yielding an exceptionally good signal-to-background ratio.

AlNi melts exhibit an intermediate range order (IRO), associated with a strong non-linear behaviour of the Ni self-diffusion coefficients as a function of composition [1]. Isotopic comparison enables a closer look on intermediate correlations, as ⁵⁸Ni scatters only coherent, whereas Ni in natural abundance is a strong incoherent scatterer. The amplitude as well as the time scale of diffusive atomic motion exhibit a strong dependence on coherent, respectively incoherent contributions to scattering, and secondly, their oscillations are in phase with the static structure factor. This data set allows a detailed investigation of the diffusion mechanism in AlNi melts. The experimental results are compared with Molecular Dynamics computer simulations.

[1] S.K. Das, J. Horbach, M.M. Koza, S. Mavila Chathoth, A. Meyer, Appl. Phys. Lett. 86, 011918 (2005)