Berlin 2012 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 29: Posters II
DY 29.26: Poster
Donnerstag, 29. März 2012, 17:00–19:00, Poster A
Thermal Conductivity of Normal Conducting and Superconducting Bulk Metallic Glasses at Very Low Temperatures — •Daniel Rothfuss1, Uta Kühn2, Andreas Fleischmann1, and Christian Enss1 — 1Kirchhoff-Institute for Physics, Heidelberg University, INF 227, 69120 Heidelberg — 2IFW Dresden, Institute for Complex Materials, P.O. Box 270116, 01171 Dresden
Bulk metallic glasses (BMG) have been produced for more than one decade, but their low temperature properties are still mostly unexplored although BMGs represent a new and very interesting kind of amorphous material with a wide range of electric and magnetic properties.
At low temperatures the physical properties of non-magnetic BMGs should be governed by atomic tunneling systems, phonons and conduction electrons as well as the interactions among these degrees of freedom.
We recently started the investigation of the thermal properties of superconducting BMGs well below Tc, as in these samples the electronic degree of freedom can be switched on and off by an external magnetic field.
We present the thermal conductivity of a Zr based BMG in the superconducting state down to 6 mK. Our results show that sufficiently far below Tc the thermal conductivity can be described by the thermal diffusion of phonons and their resonant scattering with tunneling systems. Furthermore we present the thermal conductivity of the normal conducting BMG Au49Ag5.5Pd2.3Cu26.9Si16.3
in the temperature range between 10 mK and 250 mK.
Both measurements were performed with a SQUID-based contact free technique with extremely small parasitic heating.