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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 11: Poster: Glasses and Glass Transition (joint session DY/CPP)

CPP 11.9: Poster

Montag, 11. März 2013, 17:30–19:30, Poster C

First Thermal Conductivity and Elastic Susceptibility measurements of Zr-based Bulk Metallic Glasses at Ultra Low Temperatures — •Marius Hempel, Daniel Rothfuß, Andreas Fleischmann, and Christian Enss — Kirchhoff-Institut für Physik, Heidelberg

The thermal conductivity and the elastic susceptibility of Zr-based superconducting bulk metallic glasses have been measured the first time in the temperature range down to 6 mK in order to study the interaction of atomic tunnelling systems with phonons and conducting electrons. Additional susceptibility measurements reveal a superconducting transition around 1 K.

Both, the elastic susceptibility and the thermal conductivity measurements use a novel SQUID-based contact free detection technique below 1 K which allows to dispense with a bias voltage in the case of the elastic measurements and reduces parasitic heat input during the thermal conductivity measurements.

The thermal conductivity of the bulk metallic glass Zr_52.5Ti₅Cu_17.9Ni_14.6Al₁₀ scales nearly quadratically with temperature as expected from the tunnelling model. The change of sound velocity of the of the bulk metallic glass Zr₅₅Cu₃₀Al₁₀Ni₅ shows a temperature dependence which is governed by resonant and relaxational processes. The latter are caused by the interaction with thermal phonons and quasi-particles in the vicinity of the superconducting transition.