Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 35: Caloric effects in ferromagnetic materials
MA 35.1: Vortrag
Mittwoch, 3. April 2019, 15:00–15:15, H52
A multicaloric cooling cycle that exploits hysteresis — •Tino Gottschall1,2, Adrià Gràcia-Condal3, Maximilian Fries2, Andreas Taubel2, Lukas Pfeuffer2, Lluís Mañosa3, Antoni Planes3, Konstantin P. Skokov2, and Oliver Gutfleisch2 — 1Dresden High Magnetic Field Laboratory, HZDR, Germany — 2Faculty of Materials Science, TU Darmstadt, Germany — 3Facultat de Física, Universitat de Barcelona, Barcelona, Spain
The giant magnetocaloric effect, in which large thermal changes are induced in a material on the application of a magnetic field, can be used for refrigeration applications, such as the cooling of systems from a small to a relatively large scale. However, commercial uptake is limited. We propose an approach to magnetic cooling that rejects the conventional idea that the hysteresis inherent in magnetostructural phase-change materials must be minimized to maximize the reversible magnetocaloric effect. Instead, we introduce a second stimulus, uniaxial stress, so that we can exploit the hysteresis [1]. This allows us to lock-in the ferromagnetic phase as the magnetizing field is removed, which drastically reduces the volume of the magnetic field source and so reduces the amount of expensive Nd-Fe-B permanent magnets needed for a magnetic refrigerator. The technical feasibility of this hysteresis-positive approach is demonstrated using Ni-Mn-In Heusler alloys. Our study could lead to an enhanced usage of the giant magnetocaloric effect in commercial applications.
[1] T. Gottschall et al., Nat. Mater. 17, 929 (2018).