DIRECT MEASUREMENTS OF THE MAGNETOCALORIC EFFECT

摘要

We present an experimental setup recently developed at DTU Energy Conversion for measuring specific heat and direct isothermal entropy change in a varying magnetic field (DSC device) using calorimetry. The device operates in high vacuum (～1e-6 mbar) and measurements are fully automated with respect to magnetic field and temperature control. A magnetic field source comprised of two concentric Halbach type magnets that are fixed with respect to each other through a mechanical gear supply the applied magnetic field. The applied field range is 0.001 to 1.57 T with a minimum field step size smaller than 0.01 T. The magnet control is fully integrated in software allowing measurement scans to be automated. This device is an upgrade of an existing device where it is now possible to install a sample and then run temperature scans at different magnetic fields (specific heat measurement) as well as magnetic field scans under isothermal conditions (direct isothermal entropy change measurements).