Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 7: Postersession Matter at Low Temperature: Materials

TT 7.4: Poster

Montag, 23. März 2009, 13:00–16:45, P1B

New Methode to Determine the Specific Heat of Glasses at Ultra-low Temperatures — •Angela Halfar, Andreas Fleischmann, and Christian Enss — Kirchhoff-Institut für Physik, Universität Heidelberg, D-69120 Heidelberg

The low temperature properties of glasses are governed by atomic tunneling systems. Due to the structural disorder of glasses the parameters of these atomic tunneling systems are widely distributed. This is the origin of the linear specific heat of glasses at low temperatures, which is a characteristic property of amorphous materials independent of their chemical composition. Measurements of the specific heat of dielectric glasses at ultra-low temperatures are very difficult since even small parasitic heat inputs lead to large systematic errors. To minimize such parasitic heat inputs and to minimize the addenda we have developed a contact-free methode to investigate the specific heat of insulating glasses. It is based on an optical heating system and uses the temperature dependence of the amplitude of polarisation echos as an intrisic thermometer. We shall discuss this new technique and will show first experimental results.