Contribution of low-temperature degrees of freedom to the anisotropy in Co/CoO exchange coupled bilayers

D. Venus, F. Hunte, E D Dahlberg

Research output: Contribution to journalArticle

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Abstract

Measurements of the transverse magnetic AC-susceptibility χ(T) of exchange coupled polycrystalline Co/CoO bilayers have been made via the anisotropic magnetoresistance using a small AC field of 2-5 Oe and frequencies from 40 to 400 Hz. A step increase in Reχ is observed at 50-100 K, with an accompanying dissipation peak in Imχ. This feature is independent of the CoO thickness, but its dispersion with frequency suggests a thermally activated degree of freedom with an activation energy E a∼150 K. This is consistent with a contribution to the anisotropy field due to the dynamics of the ferromagnetic rather than the antiferromagnetic grains.

Original languageEnglish (US)
Pages (from-to)191-195
Number of pages5
JournalJournal of Magnetism and Magnetic Materials
Volume286
Issue numberSPEC. ISS.
DOIs
StatePublished - Feb 1 2005

Keywords

  • Anisotropic magnetoresistance
  • Co/CoO
  • Exchange anisotropy
  • Exchange bias
  • Interfacial exchange
  • Magnetic susceptibility

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