Direct observation of cobalt precipitates in nanocrystalline Cu-Co powder synthesised by laser ablation

J. P. Ahn, Y. K. Jung, J. K. Park, Moo Young Huh

Research output: Contribution to journalArticle

Abstract

Nanocrystalline Cu-Co (Cu-25Co by atomic fraction) powder for giant magnetoresistance (GMR) application has been synthesised by laser ablation method. The effect of Co precipitating evolution on the GMR properties during annealing has been investigated using energy filtered transmission electron microscopy (EFTEM) and X-ray diffraction. The as synthesised Cu-Co powder was 10 nm in diameter and formed a solid solution with an fcc structure. On the thermal stability during annealing the Cu-Co powder, the grain growth commenced before the phase separation of Cu and Co. As the result of the phase separation, nanocrystalline fcc Co particles with an average diameter of 5 nm were uniformly dispersed in Cu matrix. The relationship between the GMR property and the microstructural evolution of Co precipitate could be understood by the compositional profile showing a sinusoidal shape from EFTEM images.

Original languageEnglish
Pages (from-to)338-342
Number of pages5
JournalPowder Metallurgy
Volume48
Issue number4
DOIs
Publication statusPublished - 2005 Dec 1

Fingerprint

Giant magnetoresistance
Laser ablation
Cobalt
Powders
laser ablation
Precipitates
precipitates
cobalt
Phase separation
Annealing
Transmission electron microscopy
transmission electron microscopy
annealing
Microstructural evolution
Grain growth
Solid solutions
Thermodynamic stability
thermal stability
solid solutions
X ray diffraction

Keywords

  • EELS
  • EFTEM
  • GMR
  • Nanocrystalline
  • Precipitation
  • Spinodal decomposition

ASJC Scopus subject areas

  • Metals and Alloys

Cite this

Direct observation of cobalt precipitates in nanocrystalline Cu-Co powder synthesised by laser ablation. / Ahn, J. P.; Jung, Y. K.; Park, J. K.; Huh, Moo Young.

In: Powder Metallurgy, Vol. 48, No. 4, 01.12.2005, p. 338-342.

Research output: Contribution to journalArticle

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N2 - Nanocrystalline Cu-Co (Cu-25Co by atomic fraction) powder for giant magnetoresistance (GMR) application has been synthesised by laser ablation method. The effect of Co precipitating evolution on the GMR properties during annealing has been investigated using energy filtered transmission electron microscopy (EFTEM) and X-ray diffraction. The as synthesised Cu-Co powder was 10 nm in diameter and formed a solid solution with an fcc structure. On the thermal stability during annealing the Cu-Co powder, the grain growth commenced before the phase separation of Cu and Co. As the result of the phase separation, nanocrystalline fcc Co particles with an average diameter of 5 nm were uniformly dispersed in Cu matrix. The relationship between the GMR property and the microstructural evolution of Co precipitate could be understood by the compositional profile showing a sinusoidal shape from EFTEM images.

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