Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 20: Poster session
MM 20.3: Poster
Dienstag, 27. März 2007, 14:45–18:00, Poster C
Relaxations in metallic glasses investigated by a broad frequency and temperature range — •Dennis Bedorf1, Thomas Koeppe1, Jörg Hachenberg1, Konrad Samwer1, Annelen Kahl2, and Ranko Richert3 — 1I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2Keck Laboratories MS 138-78 Caltech, Pasadena CA 91125, USA — 3Department of Chemistry and Biochemistry, Arizona State University, Tempe AZ 85287-1604, USA
We are interested in glassy dynamics and the atomistic processes leading to different relaxations in amorphous materials. To measure the complex elastic constants, two mechanical spectroscopy techniques were employed. The use of a double-paddle-oscillator (DPO) provides sufficient sensitivity to investigate the loss of even thin films. A DPO is driven in eigenfrequency mode at 5.4 kHz and an amorphous metallic film (PdCuSi) is evaporated onto it and measured under UHV conditions. Cooling and heating enables measurements in a broad temperature range with different heating rates.
To survey the elastic constants at higher frequencies, an ultrasonic spectroscopy technique in the MHz regime is used. The pulse-echo method is applied to a bulk metallic glass in order to obtain the shear modulus and attenuation by monitoring shear wave propagation. The results are discussed in the framework of the Cooperative Shear Model.
This work was supported financially by DFG, SFB 602 and Leibniz Programm.