A setup for direct measurement of the adiabatic temperature change in magnetocaloric materials

• In order to find a highly efficient, environmentally-friendly magnetic refrigerant, direct measurements of the adiabatic temperature change ΔTadb are required. Here, in this work, a simple setup for the ΔTadb measurement is presented. Using a permanent magnet Halbach array with a maximum magnetic field of 1.8 T and a rate of magnetic field change of 5 T/s, accurate determination of ΔTadb is possible in this system. The operating temperature range of the system is from 100 to 400 K, designed for the characterization of materials with potential for room temperature magnetic refrigeration applications. Using the setup, ΔTadb of a first-order and two second-order compounds have been studied. Results from the direct measurement for the first-order compound have been compared with ΔTadb calculated from the temperature and magnetic field-dependent specific heat data. By comparing results from direct and indirect measurements, it is concluded that for a reliable characterization of the magnetocaloric effect (MCE), direct measurement of ΔTadb should be adopted.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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