Growth and nanoscale magnetic properties of ferromagnetic nanowire encapsulated inside carbon nanotubes

Yasuhiko Hayashi, T. Fujita, T. Tokunaga, B. Jang, M. Tanemura, G. A J Amaratunga

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We synthesize ferromagnetic Co nanowire, and Co/Pd multisegment nanowires encapsulated inside multi-walled carbon nanotubes CNTs (MWCNTs) by plasma-enhanced chemical vapor deposition (PECVD). High-resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) patterns and energy dispersive X-ray spectroscopy (EDS) were used to characterize the microstructures and elemental analyses of the nanowires. Quantitative magnetization measurements of Co nanowires encapsulated inside MWCNTs were experimentally established by TEM off-axis electron holography at room temperature. The MWCNTs grew up to 100-110 nm in diameter and 1.5-1.7 μm in length. The typical bright-field TEM images revealed both Co nanowire and Co/Pd multisegment nanowires encapsulated inside vertically aligned MWCNTs on the same substrate. The composition of metal encapsulated inside MWCNTs were characterized by EDS. Experimental results revealed that the Co nanowire encapsulated inside MWCNT was always presented as the face-centered-cubic (fcc) Co structure. The component of magnetic induction was then measured to be 1.2 ± 0.1 T based on TEM off-axis electron holography results, which is lower than the expected saturation magnetization of fcc Co bulk of 1.7 T. The partial oxidation of the ferromagnetic metal during the process and the magnetization direction may play an important role in the determination of the quality of the remanent states. The ferromagnetic metal nanowires encapsulated inside CNTs demonstrate very high potential in providing the required magnetic properties, low dimensionality, and small volume for future nanoscale devices.

Original languageEnglish
Article number4957803
Pages (from-to)2488-2491
Number of pages4
JournalIEEE Transactions on Magnetics
Volume45
Issue number6
DOIs
Publication statusPublished - Jun 2009
Externally publishedYes

Fingerprint

Carbon Nanotubes
Nanowires
Carbon nanotubes
Magnetic properties
Electron holography
Ferromagnetic materials
Transmission electron microscopy
Energy dispersive spectroscopy
Magnetization
Electromagnetic induction
Saturation magnetization
Plasma enhanced chemical vapor deposition
High resolution transmission electron microscopy
Electron diffraction
Diffraction patterns
Metals
Oxidation
Microstructure
Substrates
Chemical analysis

Keywords

  • Carbon nanotubes
  • Holography
  • Magnetic materials
  • Spintronics

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials

Cite this

Growth and nanoscale magnetic properties of ferromagnetic nanowire encapsulated inside carbon nanotubes. / Hayashi, Yasuhiko; Fujita, T.; Tokunaga, T.; Jang, B.; Tanemura, M.; Amaratunga, G. A J.

In: IEEE Transactions on Magnetics, Vol. 45, No. 6, 4957803, 06.2009, p. 2488-2491.

Research output: Contribution to journalArticle

Hayashi, Yasuhiko ; Fujita, T. ; Tokunaga, T. ; Jang, B. ; Tanemura, M. ; Amaratunga, G. A J. / Growth and nanoscale magnetic properties of ferromagnetic nanowire encapsulated inside carbon nanotubes. In: IEEE Transactions on Magnetics. 2009 ; Vol. 45, No. 6. pp. 2488-2491.
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