Journal of Materials Science

, Volume 39, Issue 18, pp 5701–5709

Microstructural dependence of giant-magnetoresistance in electrodeposited Cu-Co alloys

  • T. Cohen-Hyams
  • J. M. Plitzko
  • C. J. D. Hetherington
  • J. L. Hutchison
  • J. Yahalom
  • W. D. Kaplan
Article

DOI: 10.1023/B:JMSC.0000040079.41985.6b

Cite this article as:
Cohen-Hyams, T., Plitzko, J.M., Hetherington, C.J.D. et al. Journal of Materials Science (2004) 39: 5701. doi:10.1023/B:JMSC.0000040079.41985.6b

Abstract

The relationship between the microstructure and the magnetic properties of heterogeneous Cu-Co [Cu92.5-Co7.5] (at.%) thin films prepared by electrodeposition was studied. Electron spectroscopic imaging (ESI) studies clearly revealed the evolution of the cobalt microstructure as a function of thermal treatments. The as-deposited film is composed of more than one phase; metastable Cu-Co, copper and cobalt. During annealing the metastable phase decomposes into two fcc phases; Cu and Co. Grain growth occurs with increasing annealing duration, such that the cobalt grains are more homogeneously distributed in the copper matrix. A maximum GMR effect was found after annealing at 450°C for 1.5 h, which corresponds to an average cobalt grain size of 5.5 nm according to magnetization characterization. A significant fraction of the cobalt in the Cu-Co film did not contribute to the GMR effect, due to interactions between the different magnetic grains and large ferromagnetic (FM) grains. The percolation threshold of cobalt in metastable Cu-Co alloys formed by electrodeposition is lower (less than ∼7.5 at.%) than that prepared by physical deposition methods (∼35 at.%).

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • T. Cohen-Hyams
    • 1
  • J. M. Plitzko
    • 2
  • C. J. D. Hetherington
    • 3
  • J. L. Hutchison
    • 3
  • J. Yahalom
    • 1
  • W. D. Kaplan
    • 1
  1. 1.Department of Materials EngineeringHaifaIsrael
  2. 2.Department of Molecular Structural BiologyMax-Planck-Institute of BiochemistryGermany
  3. 3.Department of MaterialsOxford UniversityUK