Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 49: POSTER II

MA 49.34: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster A

Cyclic magnetocaloric behavior of Ni-Mn-In Heusler alloys — •Tino Gottschall¹, Konstantin P. Skokov¹, Elias Palacios², Ramon Burriel², and Oliver Gutfleisch¹ — ¹TU Darmstadt, Institute of Material Science, Alarich-Weiss-Str. 16, 64287 Darmstadt, Germany — ²Institute of Materials Science of Aragon, University of Zaragoza, Spain

The origin for the inverse magnetocaloric effect in Ni-Mn based Heusler alloys is a first-order magnetostructural transition between a low temperature paramagnetic/antiferromagnetic martensite and a high temperature ferromagnetic austenite phase. In order to utilize a material as a refrigerant in a magnetocaloric cooling device both the adiabatic temperature change Δ T_ad and the entropy change Δ S should be as large as possible. For direct measurements of the adiabatic temperature change it is possible to vary the measurement speed in a broad range and also the cyclic behavior can be investigated. In order to determine the entropy change either calorimetry or magnetic measurements can be performed. Unlikely these methods are typically rather slow in comparison to the conditions in a real magnetocaloric cooling device and they do not provide any information about the reversible part. But especially for Heusler alloys with large thermal hysteresis this is a crucial issue which will be discussed in this work.

This work was supported by DFG (Grant No. SPP1599)