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Frequency- and Temperature-Dependent Ferromagnetic Resonance of Co/CoO Core-Shell Nanoparticles

Published online by Cambridge University Press:  21 March 2011

U. Wiedwald
Affiliation:
Institut für Physik, Universität Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
J. Lindner
Affiliation:
Institut für Physik, Universität Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
M. Spasova
Affiliation:
Institut für Physik, Universität Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
Z. Frait
Affiliation:
Institute of Physics, Academy of Science of the Czech Republic, Na Slovance, 18221 Prague 8, Czech Republic
M. Hilgendorff
Affiliation:
caesar research center, Department of Nanoparticle Technology, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
M. Giersig
Affiliation:
caesar research center, Department of Nanoparticle Technology, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
M. Farle
Affiliation:
Institut für Physik, Universität Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
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Abstract

Ferromagnetic Resonance experiments are used to investigate the magnetic properties of monodisperse Co/CoO core-shell nanoparticles with diameters of about 10nm. From frequency- dependent measurements at various frequencies of 9-80 GHz the g-value is determined to be 2.13 which suggests an fcc bulk-like environment of the Co atoms within the core of the particles. This result yields a direct measure of the ratio of orbital to spin magnetic moment νLS=0.065. Moreover, from temperature-dependent measurements of the resonance field the anisotropy energy is extracted and found much lower than the hcp bulk value.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

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References

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