Controlled large-scale synthesis and magnetic properties of single-crystal cobalt nanorods

M. Aslam, R. Bhobe, Nasim Alem, S. Donthu, V. P. Dravid

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

We report detailed synthesis studies of large-scale fabrication of single-crystalline cobalt nanorods using thermally evaporated gold as a conducting electrode on a nanoporous anodized aluminum oxide (AAO) template. By varying the time (i.e., adjusting the current density), it is possible to control the length of the nanorods and these rods grow in highly anisotropic face-centered (L10) phase. The large-scale isolation of these nanorods was achieved using a mild HF solution to dissolve the AAO membranes, leaving behind large scale ensemble of the isolated Co nanorods. Scanning electron microscopy and transmission electron microscopy examinations show clear evidence for metallic Co nanorods (about 100 nm in diameter) formed inside an array of AAO nanopores. We observe more uniform length of nanorods when an external magnetic field is applied during synthesis. A preferred perpendicular (shape) anisotropy is observed in these nanorod arrays. Magnetic properties indicate both coercivity and thermal activation volume increase with increasing nanorod length.

Original languageEnglish (US)
Article number074311
JournalJournal of Applied Physics
Volume98
Issue number7
DOIs
StatePublished - Oct 1 2005

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nanorods
cobalt
magnetic properties
single crystals
synthesis
aluminum oxides
coercivity
isolation
rods
templates
examination
adjusting
activation
gold
current density
membranes
conduction
transmission electron microscopy
anisotropy
fabrication

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)

Cite this

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Controlled large-scale synthesis and magnetic properties of single-crystal cobalt nanorods. / Aslam, M.; Bhobe, R.; Alem, Nasim; Donthu, S.; Dravid, V. P.

In: Journal of Applied Physics, Vol. 98, No. 7, 074311, 01.10.2005.

Research output: Contribution to journalArticle

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T1 - Controlled large-scale synthesis and magnetic properties of single-crystal cobalt nanorods

AU - Aslam, M.

AU - Bhobe, R.

AU - Alem, Nasim

AU - Donthu, S.

AU - Dravid, V. P.

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AB - We report detailed synthesis studies of large-scale fabrication of single-crystalline cobalt nanorods using thermally evaporated gold as a conducting electrode on a nanoporous anodized aluminum oxide (AAO) template. By varying the time (i.e., adjusting the current density), it is possible to control the length of the nanorods and these rods grow in highly anisotropic face-centered (L10) phase. The large-scale isolation of these nanorods was achieved using a mild HF solution to dissolve the AAO membranes, leaving behind large scale ensemble of the isolated Co nanorods. Scanning electron microscopy and transmission electron microscopy examinations show clear evidence for metallic Co nanorods (about 100 nm in diameter) formed inside an array of AAO nanopores. We observe more uniform length of nanorods when an external magnetic field is applied during synthesis. A preferred perpendicular (shape) anisotropy is observed in these nanorod arrays. Magnetic properties indicate both coercivity and thermal activation volume increase with increasing nanorod length.

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