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TT: Fachverband Tiefe Temperaturen
TT 7: Postersession Matter at Low Temperature: Materials
TT 7.3: Poster
Monday, March 23, 2009, 13:00–16:45, P1B
Low-temperature investigation of the thermal conductivity of bulk metallic glasses — •Daniel Rotfhuß, Andreas Fleischmann, and Christian Enss — Kirchhoff-Institut für Physik, Universität Heidelberg, INF 227, 69120 Heidelberg, Germany
The thermal conductivity of glasses at temperatures below 1 Kelvin is generally described by the diffusion of thermal phonons. The mean free path of the phonons is limited by scattering processes between the heat-carrying phonons and the tunneling systems in the glasses. We investigate metallic glasses where the thermal transport is due to both phonons an electrons. In superconducting metallic glasses far below Tc the phonons are dominating the conduction of heat. For the first time measurements of thermal conductivity were performed on a bulk metallic glass down to 6 mK. For this purpose we used a SQUID-based contact-free technique because of its extremly small parasitic heating. Results of amorphous Zr52.2Ti5Cu17.9Ni14.6Al10 in the superconduting state are presented which show that the thermal conductivity of the sample scales nearly quadratically in temperature. This suggests that well below Tc the heat transport of superconduting metallic glasses can be described by resonant scattering of phonons by tunneling systems just as in dielectric glasses.