Magnetic phase diagram of the ferromagnetic shape memory alloys Ni 2MnGa1-xCux

K. Endo, T. Kanomata, A. Kimura, M. Kataoka, H. Nishihara, R. Y. Umetsu, K. Obara, T. Shishido, M. Nagasako, R. Kainuma, K. R.A. Ziebeck

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

X-ray powder diffraction, permeability, magnetization and differential scanning calorimetry measurements were carried out on the magnetic shape memory alloys Ni2MnGa1-xCux (0 ≤ × ≤ 0.25). On the basis of the experimental results, the phase diagram in the temperature-concentration plane was determined for this alloy system. The determined phase diagram is spanned by the paramagnetic austenite phase (Para-A), paramagnetic martensite phase (Para-M), ferromagnetic austenite phase (Ferro-A), ferromagnetic martensite phase (Ferro-M) and the premartensite phase. It was found that the magnetostructural transition between the phases Para-A and Ferro-M can occur in the concentration region 0.12 < × ≤ 0.14 and that Ni2MnGa1-xCux has the characteristics of the phase diagram similar to those of the phase diagrams of Ni 2+xMn1-xGa and Ni2Mn1-xCu xGa. In order to understand the phase diagram, the phenomenological free energy as a function of the martensitic distortion and magnetization was constructed and analyzed.

Original languageEnglish
Pages (from-to)165-176
Number of pages12
JournalMaterials Science Forum
Volume684
DOIs
Publication statusPublished - 2011 May 17

Keywords

  • Heusler alloy
  • Phase diagram
  • Phase transition

ASJC Scopus subject areas

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

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