Effect of heat treatment on properties of Ni-Mn-Ga films prepared by a sputtering method

Makoto Ohtsuka, K. Itagaki

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)

Abstract

The effect of heat treatment on the properties of Ni-Mn-Ga films such as chemical composition, crystal structure, microstructure and transformation temperature were investigated with respect to various sputtering conditions. Ni-Mn-Ga films were deposited on a poly-vinyl alcohol substrate with a radio-frequency magnetron sputtering apparatus using Ni50Mn25Ga25 and Ni52Mn24Ga24 targets. After separating from the substrates, the films were annealed at temperatures between 873 and 1273 K for 3.6 ks. The chemical composition of the films depended on the sputtering power, but there was no dependence on the heat treatment temperature. Each deposited film had a columnar grain structure. After the heat treatment, the width of the columnar grains increased and then became indistinct with increasing heat treatment temperature. The martensitic transformation temperature increased with increasing nickel content of the films, while the Curie temperature decreased. The film heat-treated at 1073 K showed a two-way shape memory effect through the martensitic transformation and its reversion.

Original languageEnglish
Pages (from-to)49-59
Number of pages11
JournalInternational Journal of Applied Electromagnetics and Mechanics
Volume12
Issue number1-2
Publication statusPublished - 2000 Dec 1

Keywords

  • Crystal structure
  • Martensitic transformation
  • Microstructure
  • Nickel-manganese-gallium
  • Shape memory effect

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Mechanics of Materials
  • Computational Mechanics
  • Physics and Astronomy (miscellaneous)

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