Spin-torque oscillators with thermal noise: A constant energy orbit approach

D. Pinna, D. L. Stein, A. D. Kent

    Research output: Contribution to journalArticle

    Abstract

    We study the magnetization dynamics of spin-torque oscillators in the presence of thermal noise and as a function of the spin-polarization angle in a macrospin model. The macrospin has biaxial magnetic anisotropy, typical of thin film magnetic elements, with an easy axis in the film plane and a hard axis out of the plane. Using a method that averages the energy over precessional orbits, we derive analytic expressions for the current that generates and sustains out-of-plane precessional states. We find that there is a critical angle of the spin polarization necessary for the occurrence of such states and predict a hysteretic response to applied current. This model can be tested in experiments on orthogonal spin-transfer devices, which consist of both an in-plane and out-of-plane magnetized spin polarizers, effectively leading to an angle between the easy and spin-polarization axes.

    Original languageEnglish (US)
    Article number174405
    JournalPhysical Review B - Condensed Matter and Materials Physics
    Volume90
    Issue number17
    DOIs
    StatePublished - Nov 6 2014

    Fingerprint

    Spin polarization
    Thermal noise
    thermal noise
    torque
    Orbits
    Torque
    oscillators
    orbits
    Magnetic thin films
    Magnetic anisotropy
    energy
    Magnetization
    polarization
    polarizers
    Experiments
    occurrences
    magnetization
    anisotropy
    thin films

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Electronic, Optical and Magnetic Materials

    Cite this

    Spin-torque oscillators with thermal noise : A constant energy orbit approach. / Pinna, D.; Stein, D. L.; Kent, A. D.

    In: Physical Review B - Condensed Matter and Materials Physics, Vol. 90, No. 17, 174405, 06.11.2014.

    Research output: Contribution to journalArticle

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