Magnetic Nanocomposites at Microwave Frequencies

  • Jaakko V.I. TimonenEmail author
  • Robin H.A. Ras
  • Olli Ikkala
  • Markku Oksanen
  • Eira Seppälä
  • Khattiya Chalapat
  • Jian Li
  • Gheorghe Sorin Poraoanu
Part of the Engineering Materials book series (ENG.MAT.)


Most conventional magnetic materials used in the electronic devices are ferrites, which are composed of micrometer-size grains. But ferrites have small saturation magnetization, therefore the performance at GHz frequencies is rather poor. That is why functionalized nanocomposites comprising magnetic nanoparticles (e.g. composed of Fe, Co) with dimensions ranging from a few nm to 100 nm, and embedded in dielectric matrices (e.g. silicon oxide, aluminium oxide) have a significant potential for the electronics industry. When the size of the nanoparticles is smaller than the critical size for multidomain formation, these nanocomposites can be regarded as an ensemble of particles in single-domain states and the losses (due for example to eddy currents) are expected to be relatively small.

Here we review the theory of magnetism in such materials, and we present a novel measurement method used for the characterization of the electromagnetic properties of composites with nanomagnetic insertions. We also present a few experimental results obtained on composites consisting of iron nanoparticles in a dielectric matrix.


Domain Wall Relative Permeability Ferromagnetic Resonance Anisotropy Field Nanoparticle Volume Fraction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported by the Finnish Funding Agency for Technology and Innovation (TEKES). G.S.P. would like to acknowledge also partial support from the Academy of Finland (Acad. Res. Fellowship 00857 and projects 129896, 118122, and 135135). K.C. wishes to thank the Thailand Commission on Higher Education for financial support.


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Copyright information

© Springer –Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Jaakko V.I. Timonen
    • 1
    Email author
  • Robin H.A. Ras
    • 1
  • Olli Ikkala
    • 1
  • Markku Oksanen
    • 2
  • Eira Seppälä
    • 2
  • Khattiya Chalapat
    • 3
  • Jian Li
    • 3
  • Gheorghe Sorin Poraoanu
    • 3
  1. 1.Molecular Materials, Department of Applied Physics, School of Science and TechnologyAalto UniversityAaltoFinland
  2. 2.Nokia Research CenterHelsinkiFinland
  3. 3.Low Temperature Laboratory, School of Science and TechnologyAalto UniversityAaltoFinland

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