Regensburg 2010 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 30: Posters II

DY 30.16: Poster

Donnerstag, 25. März 2010, 16:00–18:00, Poster C

Thermal conductivity of superconducting bulk metallic glasses at very low temperatures — •Daniel Rotfhuß¹, Uta Kühn², Andreas Fleischmann¹, and Christian Enss¹ — ¹Kirchhoff-Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, D-69120 Heidelberg, Germany — ²IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden, Germany

Based on new production processes in the technique of casting amorphous metallic alloys a wide range of bulk metallic glasses with various electric and magnetic properties can be produced. Hereby especially superconducting bulk metallic glasses offer several advantages. Particularly with this kind of vitreous material it is possible to probe not only the interaction between tunnelling systems and phonons, but also with electrons by switching between the normal and superconducting state with an external magnetic field. But until now only little is known about the physical properties of these amorphous systems down to millikelvin temperatures.

We present the thermal conductivity of bulk amorphous Zr_52.5Ti₅Cu_17.9Ni_14.6Al₁₀ in the superconducting state down to 6mK. Measurements were performed with a SQUID-based contact free technique. Our results show that the thermal conductivity of the sample scales nearly quadratically with temperature. This suggests that far below T_c, the thermal conductivity of this bulk metallic glass can be described well by the thermal diffusion of phonons and their resonant scattering at tunnelling systems.