Characterization of superparamagnetic "core-shell" nanoparticles and monitoring their anisotropic phase transition to ferromagnetic "solid solution" nanoalloys

Jong Il Park, Min Gyu Kim, Young Wook Jun, Jae Sung Lee, Woo Ram Lee, Jinwoo Cheon

Research output: Contribution to journalArticle

165 Citations (Scopus)

Abstract

The structure, magnetism, and phase transition of core-shell type CoPt nanoparticles en route to solid solution alloy nanostructures are systematically investigated. The characterization of CocorePtshell nanoparticles obtained by a "redox transmetalation" process by transmission electron microscopy (TEM) and, in particular, X-ray absorption spectroscopy (XAS) provides clear evidence for the existence of a core-shell type bimetallic interfacial structure. Nanoscale phase transitions of the CocorePtshell structures toward c-axis compressed face-centered tetragonal (fct) solid solution alloy CoPt nanoparticles are monitored at various stages of a thermally induced annealing process and the obtained fct nanoalloys show a large enhancement of their magnetic properties with ferromagnetism. The relationship between the nanostructures and their magnetic properties is in part elucidated through the use of XAS as a critical analytical tool.

Original languageEnglish
Pages (from-to)9072-9078
Number of pages7
JournalJournal of the American Chemical Society
Volume126
Issue number29
DOIs
Publication statusPublished - 2004 Jul 28

Fingerprint

X-Ray Absorption Spectroscopy
Nanostructures
Phase Transition
Shells (structures)
Nanoparticles
Solid solutions
X ray absorption spectroscopy
Phase transitions
Monitoring
Magnetic properties
Transmission Electron Microscopy
Oxidation-Reduction
Ferromagnetism
Magnetism
Annealing
Transmission electron microscopy

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

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abstract = "The structure, magnetism, and phase transition of core-shell type CoPt nanoparticles en route to solid solution alloy nanostructures are systematically investigated. The characterization of CocorePtshell nanoparticles obtained by a {"}redox transmetalation{"} process by transmission electron microscopy (TEM) and, in particular, X-ray absorption spectroscopy (XAS) provides clear evidence for the existence of a core-shell type bimetallic interfacial structure. Nanoscale phase transitions of the CocorePtshell structures toward c-axis compressed face-centered tetragonal (fct) solid solution alloy CoPt nanoparticles are monitored at various stages of a thermally induced annealing process and the obtained fct nanoalloys show a large enhancement of their magnetic properties with ferromagnetism. The relationship between the nanostructures and their magnetic properties is in part elucidated through the use of XAS as a critical analytical tool.",
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Characterization of superparamagnetic "core-shell" nanoparticles and monitoring their anisotropic phase transition to ferromagnetic "solid solution" nanoalloys. / Park, Jong Il; Kim, Min Gyu; Jun, Young Wook; Lee, Jae Sung; Lee, Woo Ram; Cheon, Jinwoo.

In: Journal of the American Chemical Society, Vol. 126, No. 29, 28.07.2004, p. 9072-9078.

Research output: Contribution to journalArticle

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AU - Kim, Min Gyu

AU - Jun, Young Wook

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AU - Lee, Woo Ram

AU - Cheon, Jinwoo

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AB - The structure, magnetism, and phase transition of core-shell type CoPt nanoparticles en route to solid solution alloy nanostructures are systematically investigated. The characterization of CocorePtshell nanoparticles obtained by a "redox transmetalation" process by transmission electron microscopy (TEM) and, in particular, X-ray absorption spectroscopy (XAS) provides clear evidence for the existence of a core-shell type bimetallic interfacial structure. Nanoscale phase transitions of the CocorePtshell structures toward c-axis compressed face-centered tetragonal (fct) solid solution alloy CoPt nanoparticles are monitored at various stages of a thermally induced annealing process and the obtained fct nanoalloys show a large enhancement of their magnetic properties with ferromagnetism. The relationship between the nanostructures and their magnetic properties is in part elucidated through the use of XAS as a critical analytical tool.

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