Berlin 2008 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 7: Matter at Low Temperature: Poster Session

TT 7.5: Poster

Monday, February 25, 2008, 14:00–18:00, Poster B

Energy Fluctuations in Glasses at very low Temperatures — •Lena Maerten, Loredana Fleischmann, Andreas Fleischmann und Christian Enss — Kirchhoff-Institut für Physik Heidelberg

Coupling a system thermally to a heat reservoir, its energy content fluctuates according to statistical mechanics. In glasses these fluctuations are mainly caused by energy absorbing and releasing tunnelling systems. Measuring the energy content and investigating its variation should give information about relaxation times and whether or not the tunnelling processes are correlated. In our experiment we use a paramagnetic temperature sensor sputtered onto the quartz glass sample to be measured. The paramagnetic material changes its magnetization with temperature according to the Curie-Law. This change in magnetization is read out by a low noise double stage SQUID-magnetometer. In addition to the energy fluctuations described above, the time resolved heat release can be measured with this setup. Rapidly cooling the heat bath to a constant temperature, one can observe the energy dripping out of excited tunnelling systems while the sample gradually thermalizes. A detailed description of the experimental setup and first results will be presented.