Dynamics of spin torque switching in all-perpendicular spin valve nanopillars

H. Liu, D. Bedau, J. Z. Sun, S. Mangin, E. E. Fullerton, J. A. Katine, A. D. Kent

    Research output: Contribution to journalArticlepeer-review

    Abstract

    We present a systematic experimental study of the spin-torque-induced magnetic switching statistics at room temperature, using all-perpendicularly magnetized spin-valves as a model system. Three physical regimes are distinguished: a short-time ballistic limit below a few nanoseconds, where spin-torque dominates the reversal dynamics from a thermal distribution of initial conditions; a long time limit, where the magnetization reversal probability is determined by spin-torque-amplified thermal activation; and a cross-over regime, where the spin-torque and thermal agitation both contribute. For a basic quantitative understanding of the physical processes involved, an analytical macrospin model is presented which contains both spin-torque dynamics and finite temperature effects. The latter was treated rigorously using a Fokker-Plank formalism, and solved numerically for specific sets of parameters relevant to the experiments to determine the switching probability behavior in the short-time and cross-over regimes. This analysis shows that thermal fluctuations during magnetization reversal greatly affect the switching probability over all the time scales studied, even in the short-time limit.

    Original languageEnglish (US)
    Pages (from-to)233-258
    Number of pages26
    JournalJournal of Magnetism and Magnetic Materials
    Volume358-359
    DOIs
    StatePublished - May 2014

    Keywords

    • Ballistic magnetization reversal
    • Giant magnetoresistance
    • Macrospin dynamics
    • Magnetic random access memory
    • Magnetization dynamics
    • Magnetization reversal
    • Perpendicular magnetic anisotropy
    • Spin transfer torque
    • Spin transfer torque switching
    • Spin valve
    • Spintronics

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics

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