Magnetic-field induced shape memory effect in Ni2MnGa sputtered films

Makoto Ohtsuka, Masaki Sanada, Minoru Matsumoto, Kimio Itagaki

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The shape memory effect (SME) by magnetic field is interesting and important for physics and application. The Ni2MnGa films were deposited on a poly-vinyl alcohol (PVA) substrate with a radio-frequency (RF) magnetron sputtering apparatus using Ni52Mn24Ga24 or Ni52.5Mn22Ga25.5 target. After separating from the substrate, the films were heat-treated at 1073 K for 36 ks for homogenization and ordering. They were constrained in a silica tube and heated at 673 K for 14.4 and 57.6 ks. The two-way SME for each constraint-aged film was confirmed by thermal cycling. The shape change of film under magnetic field was observed at constant temperature between As* and Af*, or Ms* and Mf*. Magnetic field was applied parallel to the film surface up to 5 T using a super-conductor magnet. These films showed the SME by magnetic field. The strain by magnetic field was dependent on the measurement temperature. At temperatures between Ms* and Mf*, the strain increased with increasing magnetic field and slightly decreased with decreasing magnetic field. The martensitic transformation was induced by the magnetic field up to 5 T, which corresponds to that observed by cooling down to about 4 K.

Original languageEnglish
Pages (from-to)377-383
Number of pages7
JournalMaterials Science and Engineering A
Volume378
Issue number1-2 SPEC. ISS.
DOIs
Publication statusPublished - 2004 Jul 25

Keywords

  • Constraint-aging
  • Ferromagnetic shape memory alloy
  • Magnetic field
  • Nickel-manganese-gallium
  • Shape memory effect
  • Sputtered film

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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