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MM: Fachverband Metall- und Materialphysik
MM 21: Functional Materials II
MM 21.2: Vortrag
Montag, 20. März 2017, 17:30–17:45, IFW D
Magnetocaloric properties of melt-spun NiCoMnAl Heusler ribbons — •Bruno Weise1, Niclas Teichert2, Andreas Becker2, Lars Helmich2, Maria Krautz1, Andreas Hütten2, and Anja Waske1,3 — 1IFW Dresden, Institute for Complex Materials, Dresden, Germany — 2CSMD, Department of Physics, Bielefeld University, Bielefeld, Germany — 3Institute of Materials Science, TU Dresden, Dresden, Germany
Within the group of magnetocaloric Heusler alloys NiCoMnAl is a promising alloy system for magnetic refrigeration. It is rare-earth free, non-toxic and none of the constituent elements is short on stock. In thin films of NiCoMnAl, an entropy change of up to Δ S = 17.5 J/kgK for a magnetic field change of Δ µ0H = 5 T was observed [1], hence thin films can be used as a model system to test new materials. This subsequent study applies these results to bulk materials.
Samples of the nominal composition Ni40Co10Mn30Al20 have been produced by melt spinning to achieve near net shaped thin plates for the use in a refrigeration bed. The ribbons were annealed for up to 50 h and the structure was checked with XRD. With electron microscopy the microstructure of the ribbons was studied. An optimal heat treatment time for highest entropy change was found and the adiabatic temperature change for this annealing time was determined.
[1] N. Teichert et al., Phys. Rev. B 91, 184405 (2015).