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DY: Fachverband Dynamik und Statistische Physik

DY 10: Posters I

DY 10.15: Poster

Montag, 14. März 2011, 17:00–19:00, P4

Thermal Conductivity of 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

As a new kind of vitreous material bulk metallic glasses offer several advantages for the investigation of glassy materials at very low temperatures. Particularly with superconducting bulk metallic glasses it is possible to probe not only the interaction between tunnelling systems and electrons, but also with phonons by switching between the normal and superconducting state with an external magnetic field. But until now only little is known about their properties down to milli-kelvin temperatures. The only existing measurements of thermal conductivity of bulk metallic glasses do not reach much below 1K or are performed on thin films down to 100mK. We present the thermal conductivity of bulk amorphous Zr_52,2Ti₅Cu_17,9Ni_14,6Al₁₀ in the superconducting state down to 6mK. Measurements were performed with a novel SQUID-based contact free technique because of its extremely small parasitic heating. Our results show that the thermal conductivity of the sample scales nearly quadratically with temperature. This suggests that sufficient below the critical temperature 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.