High-Performance Thermomagnetic Generators Based on Heusler Alloy Films

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

研究成果: Article査読

32 被引用数 (Scopus)

抄録

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 of the films, a periodic temperature change of only 3 K is required for operation. The duration of thermomagnetic duty cycle is only about 12 ms, which matches with the period of oscillatory motion.

本文言語English
ジャーナルAdvanced Energy Materials
7
5
DOI
出版ステータスPublished - 2017 3 8

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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