Structure and magnetic properties of ferromagnetic nanowires in self-assembled arrays

H. Zeng, R. Skomski, L. Menon, Y. Liu, S. Bandyopadhyay, D. J. Sellmyer

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Abstract

Static and dynamic aspects of the magnetization reversal in nanowire arrays are investigated. The arrays have been produced by electrodeposition of ferromagnetic metals (Fe, Co, and Ni) into porous anodic alumina templates, with diameters as small as 5 nm. The crystal structures of the nanowires are bcc (Fe) and fcc (Ni) and a mixture of fcc and hep (Co), with grain sizes of a few nanometers. Magnetic properties as a function of temperature are investigated. The temperature dependence of coercivity can be understood in terms of thermal activation over an energy barrier with a 3/2-power dependence on the field. Coercivity as a function of diameter reveals a change of the magnetization reversal mechanism from localized quasicoherent nucleation for small diameters to a localized curlinglike nucleation as the diameter exceeds a critical value determined by the exchange length. The quasicoherent limit is described by a model that yields explicitly real-structure-dependent expressions for coercivity, localization length, and activation volume.

Original languageEnglish (US)
Article number134426
Pages (from-to)1344261-1344268
Number of pages8
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume65
Issue number13
StatePublished - Apr 1 2002

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Zeng, H., Skomski, R., Menon, L., Liu, Y., Bandyopadhyay, S., & Sellmyer, D. J. (2002). Structure and magnetic properties of ferromagnetic nanowires in self-assembled arrays. Physical Review B - Condensed Matter and Materials Physics, 65(13), 1344261-1344268. [134426].