Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 34: Poster Session
MM 34.3: Poster
Dienstag, 1. April 2014, 18:00–20:00, P4
Optimization of a Nanocalorimeter inside an SEM — •Emanuel Franke1, Cynthia A. Volkert1, Feng Yi2, and David A. LaVan2 — 1Institut für Materialphysik, Georg-August-University, Göttingen, 37077 Göttingen — 2Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, USA 20899
As sample length scales reach down to nanometers and the surface to volume ratio becomes large, the thermal properties of materials are changed. The involved energy in such size induced changes is often only a few nano-Joules and cannot be measured by conventional calorimetry which has too low sensitivity. MEMS-based nanocalorimeters with sufficient resolution to measure with nJ resolution have been developed in the last two decades. We present several proof-of-concept experiments using a MEMS based differential calorimeter which has been installed in a field emission SEM. The SEM allows careful observation of the experimental conditions and of any changes in the sample microstructure due to thermal cycling. Enthalpy change can be measured from room temperature up to 1000 K by applying heating rates from 104 K/s to 105 K/s. Sensitivity better than 1 nJ/K for reversible and 10 nJ/K for irreversible processes can be achieved. The limits of the measurement method are explored by studying dewetting and oxidation of copper films and melting of bismuth nanoparticles.