Berlin 2005 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.26: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

High Sensitive AC-calorimeter for Nanometer Sized Samples — •Heiko Huth, Alexander Minakov, and Christoph Schick — Universität Rostock, Institut für Physik, Universitätsplatz 3, Rostock 18051

For nanogram samples and films in the µm…nm range standard calorimetric methods are mostly not applicable. To overcome these limitations one can measure with high heating and cooling rates. This is realized by the use of chip calorimeters. These calorimeters use thin film techniques to avoid large addenda heat capacities. With the use of small samples this results in possible heating rates up to 100,000 K/s. These chip calorimeters can also be used to measure frequency dependent heat capacity. We use a standard vacuum gauge from Xensor Integration, NL, as an AC-Calorimeter. On a thin membrane of silicon-nitride a small heater is placed with the hot junctions of a thermopile around. The sample is placed on the heater in case of small samples or spread over the whole sensor using spin coating in case of thin films. In this case only the heated area is of interest. The achieved high sensitivity gives us the possibility to measure samples below one nanogram or heat capacities below 1 nJ/K. Choosing the right experimental conditions a frequency range between about 1 Hz and 1 kHz is accessible.