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MA: Fachverband Magnetismus
MA 61: Caloric Effects
MA 61.1: Vortrag
Freitag, 20. März 2020, 09:30–09:45, HSZ 101
On the exploration of mechanical and magnetic properties of Ni-Mn-In Heusler alloy system doped with Gd — •Wei Liu, Franziska Scheibel, Lukas Pfeuffer, Andreas Taubel, Konstantin Skokov, and Oliver Gutfleisch — Funktional Materials, Technische Universität Darmstadt
NiMn- based Heusler alloys can be used in a six-step multistimuli cooling cycle which combines the magnetocaloric effect and the elastocaloric effect. This multistimuli cooling cycle has been demonstrated to be able to exploit the thermal hysteresis to achieve a fully reversible caloric effect [1]. However, the brittleness of NiMn- based Heusler alloys is problematic for cyclic application with stress. A possible method to strengthen them is precipitation hardening. By doping with Gd we introduced Gd-rich precipitates to the Ni-Mn-In system. With a slight increase of the hysteresis and a slight decrease of the transition steepness, the magnetic entropy change of the doped sample of 9 J kg−1 K−1 can be largely retained, compared to the undoped sample with a value of 11 J kg−1 K−1 . An adiabatic temperature change of 4 K is measured in the Gd-doped sample under 2 T, whereas the value for the undoped sample is 5 K. The compressive tests show that the compressive stress is increased by almost 3 times by doping, which is beneficial for the multi-stimuli cooling cycle. The work is supported by the ERC (Project ’Cool Innov’) and DFG (Grant No. SPP 1599). [1] T. Gottschall, A. Gràcia-Condal, M. Fries, A. Taubel, L. Pfeuffer, L. Mañosa, A. Planes et al., A multicaloric cooling cycle that exploits thermal hysteresis, Nature materials 17 (2018) 929*934.