Assoc. Prof. Andreas Rydh, Experimental Condensed Matter Physics, Department of Physics, Stockholm University
Nanocalorimetry: multimodal possibilities with thermodynamic characterization
Time: Thu 2017-03-30 09.00 - 11.00
Title: Nanocalorimetry: multimodal possibilities with thermodynamic characterization
Abstract. In materials research, calorimetry provides a basic thermodynamic characterization that directly relates to the various degrees of freedom of the material depending on conditions such as temperature and applied magnetic field. Specific heat measurements are sensitive to phase transitions and effects of fluctuations, and can provide details on critical exponents and order parameters such as those involved in superconductivity, nematic order, magnetism, and structural transitions/distortions. For a complete understanding of systems with such orders, complementary transport, magnetic, and structural measurements are usually needed. Ideally, measurements should be performed on the same sample in order to avoid spurious effects due to inhomogeneity, history, variations in doping, or differences in absolute temperature. Enabled through nanofabrication and developments in measurement electronics, we have combined a membrane-based nanocalorimeter with concurrent synchrotron x-ray measurements in applied magnetic fields at low temperature. In this setup, the calorimeter acts both as a high-resolution ac calorimeter probe and as sample platform, where the sample temperature can be locally controlled and monitored, keeping the cryostat at base temperature. This alleviates beam alignment of small samples and further allows the calorimeter to be used as an in-situ x-ray absorption spectroscopy detector.