Thermally induced magnetic switching in thin ferromagnetic annuli

Kirsten Martens, D. L. Stein, A. D. Kent

    Research output: Contribution to journalConference articlepeer-review


    We consider magnetization reversal due to thermal fluctuations in thin, submicron-scale rings. These mesoscopic ferromagnetic particles are of particular interest as potential information storage components in magnetoelectronic devices, because their lack of sharp ends result in a magnetization density that is significantly more stable against reversal than in thin needles and other geometries. Their two-dimensional nature and rotational symmetry allow us to incorporate long-range magnetostatic forces in a fully analytic treatment, which is not possible in most geometries. We uncover a type of 'phase transition' between different activation regimes as magnetic field is varied at fixed ring size. Previous studies of such transitions in classical activation behavior have found that they occur as length is varied, which cannot be realized easily or continuously for most systems. However, the different activation regimes in a single mesoscopic ferromagnet should be experimentally observable by changing the externally applied magnetic field, and by tuning this field the transition region itself can be studied in detail.

    Original languageEnglish (US)
    Article number03
    Pages (from-to)1-11
    Number of pages11
    JournalProceedings of SPIE - The International Society for Optical Engineering
    StatePublished - 2005
    EventNoise in Complex Systems and Stochastic Dynamics III - Austin, TX, United States
    Duration: May 24 2005May 26 2005


    • Kramers theory
    • Magnetic rings
    • Magnetic switching
    • Magnetization reversal
    • Micromagnetics
    • Nanomagnets
    • Néel-Brown theory
    • Stochastic escape
    • Thermal fluctuations

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Computer Science Applications
    • Applied Mathematics
    • Electrical and Electronic Engineering


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