Phase equilibria and magnetic properties of Heusler-type ordered phases in the Co-Mn-Ga ternary system

K. Minakuchi, R. Y. Umetsu, K. Kobayashi, M. Nagasako, R. Kainuma

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Phase equilibria at 800, 900 and 1000°C, as well as order-disorder and magnetic transitions of Heusler-type ordered phase were investigated in the Co-Mn-Ga ternary system. The β phase with bcc structure including the Heusler-type ordered phase exists in a wide composition range of the ternary system. It was confirmed by STEM-HAADF observation that the crystal structure of the Heusler-type ordered alloy Mn2CoGa is L21b-type Fm3¯m (i.e., (Mn,Co)2MnGa), but not inverse-Heusler (Hg2CuTi) type F4¯3m. The L21/B2 order-disorder transition temperature shows a maximum at the stoichiometric composition of Co2MnGa and the Curie temperature of the L21 phase decreases with increasing Ga content. Magnetic moments converted from magnetization curves at 4.2 K for CoxMn(76-x)Ga24 alloys well follow the generalized Slater-Pauling rule in the composition of 25 ≤ x ≤ 50, and magnetization curves indicate very small high-field magnetic susceptibility.

Original languageEnglish
Pages (from-to)577-585
Number of pages9
JournalJournal of Alloys and Compounds
Volume645
DOIs
Publication statusPublished - 2015 Jun 4

Keywords

  • Curie temperature
  • Magnetic moment
  • Order-disorder transition
  • Phase equilibria

ASJC Scopus subject areas

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

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