AVS 51st International Symposium
    Magnetic Interfaces and Nanostructures Thursday Sessions
       Session MI-ThA

Invited Paper MI-ThA9
Ferromagnetic Resonance: An Ultimate Tool to Study the Dynamical Response of Nanostructured Magnetic Systems

Thursday, November 18, 2004, 4:40 pm, Room 304A

Session: Molecular Spintronics and Dynamics
Presenter: J. Lindner, Universität Duisburg-Essen, Germany
Authors: J. Lindner, Universität Duisburg-Essen, Germany
K. Baberschke, Freie Universität Berlin, Germany
M. Farle, Universität Duisburg-Essen, Germany
Correspondent: Click to Email
Ferromagnetic resonance (FMR) measurements probe the dynamical response of magnetic systems subsequent to an excitation within the microwave regime. Due to the high sensitivity of FMR this technique is well suited for the investigation of nanostructures and ultrathin magnetic films or multilayers@footnote 1@. As the resonance condition is determined by internal fields in the sample like anisotropy fields or interlayer coupling fields within layered structures, FMR experiments give a direct access to these quantities based on an analysis that uses the Landau-Lifshitz equation of motion. This will be demonstrated for the case of Ni/Cu/Ni and Ni/Cu/Co films grown epitaxially on Cu(100) subtrates. A unique possibility to grow and measure the films within an ultrahigh vacuum environment allows to stepwise study the layered structures and, thus, also to investigate the effect of capping layers. Besides investigating the FMR resonance field a careful analysis of the FMR linewidth yields information about relaxation processes within the magnetic system. From frequency dependent experiments we show for the case of Fe/V multilayers that a purely Gilbert-like damping term is not sufficient to explain the observed values of the linewidth@footnote 2@. In this system the relaxation is strongly influenced by the decay of the uniform precession mode due to two-magnon processes. Finally, also within laterally structured systems FMR can be applied to study magnetic properties. This is demonstrated for the case of monodisperse Co/CoO core/shell particles of about 10nm diameter, for which the temperature dependence of the anisotropy energy is discussed. @FootnoteText@ @footnote 1@ J. Lindner, K. Baberschke, J. Phys.: Condens. Matter 15, R193 (2003); S465 (2003).@footnote 2@ J. Lindner, K. Lenz, E. Kosubek, K. Baberschke, D. Spoddig, R. Meckenstock, J. Pelzl, Z. Frait, D. L. Mills, Phys. Rev. 68, 060102(R) (2003).