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MM: Fachverband Metall- und Materialphysik

MM 18: Topical Session Glass Dynamics V

MM 18.2: Vortrag

Dienstag, 23. März 2010, 10:45–11:00, H16

Relaxation processes in metallic glasses studied by mechanical spectroscopy — •Dennis Bedorf, Moritz Schwabe, Stefan Küchemann, Hannes Wagner, Walter Arnold, and Konrad Samwer — I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

We are interested in understanding fundamental relaxation process in glasses, especially in metallic glasses. The use of different mechanical spectroscopy techniques enables us to get an insight of the relaxation processes with a broad range of frequencies. It is also possible to compare the relaxation behavior of samples with length scales from cm down to nm. Annealing experiments reveal reversible relaxations in bulk samples for a temperature regime, where only the β-process is commonly observed [1]. Relevant length scales of dynamic heterogeneities can be obtained from measurements under reduced sample sizes or with local probing techniques. Mechanical loss measurements of thin films indicate a critical length scale of ≈ 30 nm for the activation of slow β-processes, while local probing, using an atomic force acoustic microscope (AFAM), demonstrates the heterogeneity of the local indentation modulus.

[1] A. Kahl, T. Koeppe, D. Bedorf, R. Richert, M. L. Lind, M. D. Demetriou, W. L. Johnson, W. Arnold, and K. Samwer, APL, 95, 201903 (2009)