Ferromagnetic resonance study of Co/Pd/Co/Ni multilayers with perpendicular anisotropy irradiated with helium ions

J. M.L. Beaujour, A. D. Kent, D. Ravelosona, I. Tudosa, E. E. Fullerton

    Research output: Contribution to journalArticle

    Abstract

    We present a ferromagnetic resonance (FMR) study of the effect of helium ion irradiation on the magnetic anisotropy, the linewidth and the Gilbert damping of a Co/Ni multilayer coupled to Co/Pd bilayers. The perpendicular magnetic anisotropy decreases linearly with He ion fluence, leading to a transition to in-plane magnetization at a critical fluence of 5× 10 14 ions/cm2. We find that the damping is nearly independent of fluence but the FMR linewidth at fixed frequency has a maximum near the critical fluence, indicating that the inhomogeneous broadening of the FMR line is a nonmonotonic function of the He ion fluence. Based on an analysis of the angular dependence of the FMR linewidth, the inhomogeneous broadening is associated with spatial variations in the magnitude of the perpendicular magnetic anisotropy. These results demonstrate that ion irradiation may be used to systematically modify the magnetic anisotropy and distribution of magnetic anisotropy parameters of Co/Pd/Co/Ni multilayers for applications and basic physics studies.

    Original languageEnglish (US)
    Article number033917
    JournalJournal of Applied Physics
    Volume109
    Issue number3
    DOIs
    StatePublished - Feb 1 2011

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

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