Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session

MM 20.4: Poster

Dienstag, 27. März 2007, 14:45–18:00, Poster C

Dynamics in glass forming Pd₄₀Cu₄₀P₂₀ melts — •Suresh Mavila Chathoth¹, Bernd Damaschke¹, Michael Marek Koza², Ranko Richert³, and Konrad Samwer¹ — ¹I. Physikalisches Institut, Universitaet Göttingen, 37077 Göttingen, Germany — ²Institut Laue-Langevin,BP 156 - 38042 Grenoble, France — ³Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, U.S.A.

The Cu relaxational dynamics and temperature dependence of self-diffusion in the glass forming Pd₄₀Cu₄₀P₂₀ melts has been investigated with inelastic neutron scattering. Unlike in Pd₄₀Ni₄₀P₂₀ or Pd₄₃Ni₁₀Cu₂₇P₂₀ [1] melts self-diffusion in Pd₄₀Cu₄₀P₂₀ melt approaches similar values at high temperature but anomalously faster on approaching its liquidus temperature. The intermediate scattering function, Φ(q,t) of Pd₄₀Cu₄₀P₂₀ melts decay to zero rather non-exponentially. A fitting with Kohlrausch-Williams-Watts function in the α-relaxation regime exhibits structural relaxation that shows stretching in time. Moreover Φ(q,t) shows temperature and q dependent stretching and is more pronounced at lower temperatures. This indicates that in the Pd₄₀Cu₄₀P₂₀ melts the increase in heterogeneities on cooling towards its liquidus temperature is responsible for the anomalous behavior in the self-diffusivity. We gratefully acknowledge financial support from the Leibniz program.

[1] S. M. Chathoth, A. Meyer, M.M. Koza, F. Juranyi, Appl. Phys. Lett. 85, 4881 (2004).