Giant magnetoresistance in electrodeposited multilayer films. The influence of superparamagnetic regions

I. Bakonyi, L. Péter, V. Weihnacht, J. Tóth, L. F. Kiss, C. M. Schneider

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

When preparing an alternating sequence of magnetic (Co or Ni) and non-magnetic (Cu) layers by electrodeposition using the two-pulse plating technique, a dissolution of the less-noble magnetic Co and Ni atoms can take place during the deposition of the more noble and non-magnetic Cu atoms. This process results in changes of the actual sublayer thicknesses with respect to the nominal values and can also cause some chemical intermixing at the magnetic/non-magnetic interfaces. As a consequence, superparamagnetic (SPM) regions with "loose magnetic moments" can form as has been demonstrated for electrodeposited Ni-Cu/Cu multilayers. We have also shown recently for electrodeposited Co-Cu/Cu multilayers that if some fraction of the magnetic layers exhibits SPM behaviour then the observed giant magnetoresistance (GMR) can be quantitatively decomposed into a ferromagnetic (FM) and a SPM contribution. In this paper, the results of a similar GMR decomposition study are presented for two electrodeposited Co-Cu/Cu multilayers. In the multilayer with strongly non-saturated magnetoresistance curves, the dominant GMR term was due to SPM regions, whereas in the other multilayer for which the magnetoresistance is mostly saturated in magnetic fields around 1 to 2 kOe, the FM contribution to the GMR is much larger. At the same time, magnetic measurements on the first multilayer sample have also revealed the presence of a large SPM contribution to the magnetization.

Original languageEnglish
Pages (from-to)589-598
Number of pages10
JournalJournal of Optoelectronics and Advanced Materials
Volume7
Issue number2
Publication statusPublished - Apr 1 2005

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Keywords

  • Electrodeposited multilayers
  • Giant magnetoresistance (GMR)
  • Superparamagnetism (SPM)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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