Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 35: Caloric effects in ferromagnetic materials

MA 35.7: Vortrag

Mittwoch, 3. April 2019, 16:30–16:45, H52

Magnetocaloric potential of Ni-Mn-(In,Sn,Al) Heusler alloys in case of complete martensite-to-austenite transformation in high magnetic fields — •Franziska Scheibel¹, Andreas Taubel¹, Lukas Pfeuffer¹, Tino Gottschall², and Oliver Gutfleisch¹ — ¹Funktionale Materialien, Technische Universität Darmstadt, Germany — ²Hochfeld- Magnetlabor Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Germany

Ni-Mn-based Heusler are known as potential materials for magnetic refrigeration, due to their large magnetocaloric effect during first-order magnetostructural transformation (FOMST). The challenge of the thermal hysteresis of the FOMST becomes an advantage by using a new cooling cycle concept, which introduces a second stimulus (uniaxial stress) besides the magnetic field^[1]. The new concept enables the reduction of the permanent magnet volume and the duration of the magnetic field application which allows an increase in the field.
We show the magnetocaloric potential of Ni-Mn-(In, Sn, Al) Heusler alloys by direct adiabatic temperature change Δ T_ad measurements in pulsed magnetic fields up to 30 T inducing a complete martensite-to-austenite transformation. Thereby, the MCE of different Heusler alloys can be compared by considering the max. Δ T_ad for a complete transformation rather than comparing minor-loop transformation in 1 or 2 T. As an example, a Δ T_ad of -17 K is measured in Ni₄₆Mn₃₈Sn₁₁Co₅ for a 20 T field pulse.
The work is supported by the ERC advanced grand *Cool Innov*.
^[1] T. Gottschall et al., Nature Materials 17, 929-934 (2018)