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High-Performance Thermomagnetic Generators Based on Heusler Alloy Films

Gueltig, Marcel; Wendler, Frank; Ossmer, Hinnerk; Ohtsuka, Makoto; Miki, Hiroyuki; Takagi, Toshiyuki; Kohl, Manfred

Abstract (englisch):
Recent developments on Heusler alloys including Ni–Mn–X and Ni–Co–Mn–X (X = Ga, In, Sn,…) demonstrate multiferroic phase transformations with large abrupt changes in lattice parameters of several percent and corresponding abrupt changes in ferromagnetic ordering near the transition temperatures. These materials enable a new generation of thermomagnetic generators that convert heat to electricity within a small temperature difference below 5 K. While thermodynamic calculations on this energy conversion method predict a power density normalized to material volume of up to 300 mW cm−3, experimental results have been in the range of µW cm−3. Challenges are related to the development of materials with bulk-like single-crystal properties as well as geometries with large surface-to-volume ratio for rapid heat exchange. This study demonstrates efficient thermomagnetic generation via resonant actuation of freely movable thin-film devices of the Heusler alloy Ni–Mn–Ga with unprecedented power density of 118 mW cm−3 that compares favorably with the best thermoelectric generators. Due to the large temperature-dependent change of magnetization o ... mehr

Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.1002/aenm.201601879
ISSN: 1614-6832, 1614-6840
KITopen ID: 1000062636
HGF-Programm 43.22.01; LK 01
Erschienen in Advanced energy materials
Band 7
Heft 5
Seiten 1601879/1-7
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