Structural control of ultra-fine CoPt nanodot arrays via electrodeposition process

Siggi Wodarz, Takashi Hasegawa, Shunji Ishio, Takayuki Homma

    Research output: Contribution to journalArticle

    1 Citation (Scopus)

    Abstract

    CoPt nanodot arrays were fabricated by combining electrodeposition and electron beam lithography (EBL) for the use of bit-patterned media (BPM). To achieve precise control of deposition uniformity and coercivity of the CoPt nanodot arrays, their crystal structure and magnetic properties were controlled by controlling the diffusion state of metal ions from the initial deposition stage with the application of bath agitation. Following bath agitation, the composition gradient of the CoPt alloy with thickness was mitigated to have a near-ideal alloy composition of Co:Pt =80:20, which induces epitaxial-like growth from Ru substrate, thus resulting in the improvement of the crystal orientation of the hcp (002) structure from its initial deposition stages. Furthermore, the cross-sectional transmission electron microscope (TEM) analysis of the nanodots deposited with bath agitation showed CoPt growth along its c-axis oriented in the perpendicular direction, having uniform lattice fringes on the hcp (002) plane from the Ru underlayer interface, which is a significant factor to induce perpendicular magnetic anisotropy. Magnetic characterization of the CoPt nanodot arrays showed increase in the perpendicular coercivity and squareness of the hysteresis loops from 2.0 kOe and 0.64 (without agitation) to 4.0 kOe and 0.87 with bath agitation. Based on the detailed characterization of nanodot arrays, the precise crystal structure control of the nanodot arrays with ultra-high recording density by electrochemical process was successfully demonstrated.

    Original languageEnglish
    Pages (from-to)52-58
    Number of pages7
    JournalJournal of Magnetism and Magnetic Materials
    Volume430
    DOIs
    Publication statusPublished - 2017 May 15

    Fingerprint

    agitation
    Electrodeposition
    electrodeposition
    baths
    Coercive force
    Crystal structure
    Electron beam lithography
    Magnetic anisotropy
    coercivity
    Hysteresis loops
    Chemical analysis
    Crystal orientation
    Metal ions
    Magnetic properties
    Electron microscopes
    crystal structure
    Substrates
    metal ions
    lithography
    electron microscopes

    Keywords

    • Bit-patterned media
    • CoPt alloy
    • Electrodeposition
    • Nanodot array
    • Structural control

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics

    Cite this

    Structural control of ultra-fine CoPt nanodot arrays via electrodeposition process. / Wodarz, Siggi; Hasegawa, Takashi; Ishio, Shunji; Homma, Takayuki.

    In: Journal of Magnetism and Magnetic Materials, Vol. 430, 15.05.2017, p. 52-58.

    Research output: Contribution to journalArticle

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