Magnetization reversal and switching field of CoPt/Ru patterned films

K. Mitsuzuka, T. Shimatsu, T. Shimatsu, H. Muraoka, Nobuaki Kikuchi, J.C. Lodder

    Research output: Contribution to journalArticleAcademicpeer-review


    Dot arrays with diameter D = 80-245 nm were made from Co80Pt20 (20 nm) films with a large perpendicular anisotropy energy. Coercivity increases as D decreases, and reaches 7.6 kOe at D = 80 nm. The switching volume for the dot arrays, estimated from the field sweep-rate dependence of the coercivity, was very small in comparison with the dot volume: about 7% of the dot volume when D = 140 nm, for instance. However, the angular dependence coercivity of these dots exibits a typical rotational type of magnetization reversal. Moreover, MFM images revealed that all the dots show a single domain state during the magnetization reversal. Comparison of the coercivity and the anisotropy field suggests that the reversal process starts from a nucleation at the center of the dot followed by a propagation process. This possibility was confirmed by numerical calculation. It was estimated that the switching field distribution, SFD, of dot arrays was mainly due to the distributions of the c-axis of the hcp-CoPt lattice and the dot diameter. Calculated results indicate that the magneto-static coupling between the dot arrays must be a dominant factor in determining the SFD value when the dots are used for patterned media with a recording density of ∼1 Tbits/inch2.
    Original languageUndefined
    Article number10.3379/jmsjmag.30.100
    Pages (from-to)100-107
    Number of pages8
    JournalJournal of the Magnetics Society of Japan
    Issue number10/2
    Publication statusPublished - 2006


    • METIS-248226
    • EWI-10787
    • TST-SMI: Formerly in EWI-SMI
    • TST-uSPAM: micro Scanning Probe Array Memory
    • IR-61852

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