Magnetic entropy and magnetocaloric effect of ferromagnetic Heusler alloys Ni2Mn0.75Cu0.25Ga and Ni2MnGa 0.88Cu0.12

Takuo Sakon, Hitoshi Nagashio, Kenta Sasaki, Seiji Susuga, Keita Endo, Hiroyuki Nojiri, Takeshi Kanomata

Research output: Contribution to journalArticlepeer-review

Abstract

The magneto-structural transformation and the associated magnetic entropy change were studied in the ferromagnetic shape memory alloys Ni 2Mn0.75Cu0.25Ga and Ni2MnGa 0.88Cu0.12 by using magnetization measurements performed around the martensite transformation temperature TM and the Curie temperature TC. The direct transition from the paramagnetic austenite phase (PM phase) to the ferromagnetic martensite phase (FM phase) was observed in both alloys. In a magnetic field of 2.0 T, the Ni2Mn 0.75Cu0.25Ga and Ni2MnGa0.88Cu 0.12 alloys showed large magnetic entropy changes of -ΔS M = 15.2 J/kg K at 302 K and -7.5 J/kg K at 333 K, respectively. The magnetic entropy change of Ni2Mn0.75Cu0.25Ga is larger than that of the polycrystalline Ni2.19Mn0.81Ga alloy. Theoretical calculations were also performed, and they agreed well with the experimental determinations of -ΔSM.

Original languageEnglish
Pages (from-to)S376-S379
JournalJournal of Alloys and Compounds
Volume577
Issue numberSUPPL. 1
DOIs
Publication statusPublished - 2013 Nov 15

Keywords

  • Heusler alloys
  • Magnetic entropy change
  • Magnetization
  • Magnetocaloric effect
  • Phase transition
  • Shape memory alloys

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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