Electron microscopy study of preferential variant selection in copt alloy ordered under a magnetic field

Hiroshi Akamine, Sahar Farjami, Masatoshi Mitsuhara, Minoru Nishida, Takashi Fukuda, Tomoyuki Kakeshita

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Transmission electron microscope (TEM) and scanning transmission electron microscope (STEM) observations were carried out to investigate microstructure formation and variant selection process in L10-type ordered CoPt alloy upon a two-step ordering heat-treatment. The first step corresponds to nucleation process carried out under a magnetic field of 10 T and the second step represents growth process without magnetic field. After the first step of ordering, ordered domains of about 5 nm in size were observed and fraction of the preferred variant with the c-axis parallel to applied magnetic field was slightly higher than that of the other two variants. Formation of tweed microstructure along {011}L10 was confirmed at the initial stage of ordering. This structure is considered to be derived from the periodic alignment of interface between two ordered variants with twin relation. At the early stage of the second step of ordering, numerous micro-twins were formed through tweed microstructure and the volume fraction of the preferred variant was increased accompanying with modulation of twins, while that of other two variants was decreased. After the second step of ordering, the twins were vanished and single variant was obtained.

Original languageEnglish
Pages (from-to)1715-1718
Number of pages4
JournalMaterials Transactions
Volume54
Issue number9
DOIs
Publication statusPublished - 2013

All Science Journal Classification (ASJC) codes

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

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