Micromagnetic study of magnetization reversal in ferromagnetic nanorings

Gabriel D. Chaves-O'Flynn, A. D. Kent, D. L. Stein

    Research output: Contribution to journalArticle

    Abstract

    We present results of micromagnetic simulations of thin ferromagnetic rings undergoing magnetization reversal. This geometry is one of few examples in micromagnetics in which the transition states have been found analytically in a one-dimensional (1D) model. According to this model, at low fields and large ring sizes, the energetically preferred transition state is a localized magnetization fluctuation (instanton saddle). At high fields and small ring size, the preferred saddle state is a uniformly rotated magnetization (constant saddle). In the first part of this paper, we use numerical micromagnetic simulations to test these predictions of the 1D analytical model for more realistic situations including a variety of ring radii, annular widths and magnetic fields. The predicted activation energies for magnetization reversal are found to be in close agreement with numerical results even for rings with a large annular width where the 1D approximation would be expected to break down. We find that this approximation breaks down only when the ring's annular width exceeds its radius. In the second part, we present new metastable states found in the large radius limit and discuss how they provide a more complete understanding of the energy landscape of magnetic nanorings.

    Original languageEnglish (US)
    Article number184421
    JournalPhysical Review B - Condensed Matter and Materials Physics
    Volume79
    Issue number18
    DOIs
    StatePublished - May 1 2009

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    Nanorings
    Magnetization reversal
    Magnetization
    magnetization
    rings
    saddles
    Analytical models
    Activation energy
    Magnetic fields
    radii
    Geometry
    Computer simulation
    breakdown
    instantons
    approximation
    metastable state
    simulation
    activation energy
    geometry
    predictions

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Electronic, Optical and Magnetic Materials

    Cite this

    Micromagnetic study of magnetization reversal in ferromagnetic nanorings. / Chaves-O'Flynn, Gabriel D.; Kent, A. D.; Stein, D. L.

    In: Physical Review B - Condensed Matter and Materials Physics, Vol. 79, No. 18, 184421, 01.05.2009.

    Research output: Contribution to journalArticle

    Chaves-O'Flynn, Gabriel D. ; Kent, A. D. ; Stein, D. L. / Micromagnetic study of magnetization reversal in ferromagnetic nanorings. In: Physical Review B - Condensed Matter and Materials Physics. 2009 ; Vol. 79, No. 18.
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