Ordering of island-like FePt crystallites with orientations

Bo Bian, Kazuhisa Sato, Yoshihiko Hirotsu, Akihiro Makino

    Research output: Contribution to journalArticle

    77 Citations (Scopus)

    Abstract

    Thin films of oriented island-like crystallites of L10 FePt separated by amorphous (a-) Al2O3 were fabricated. The process took advantage of the overgrowth of α-Fe on Pt "seed" particles epitaxially grown on (100) NaCl and MgO substrates and the ordering reaction between Fe and Pt upon annealing at temperatures higher than 500°C. The coercivities of the annealed (600°C for 6 h) a-Al2O3/Fe(1 nm)/Pt (1.5 nm) films on both the NaCl (100) and MgO (100) substrates are higher than 3.3 kOe. Transmission electron microscopy observation showed that the film consisted of oriented L10 FePt island-like crystals with an average size of 12 nm and a separation of 4 nm. It was found that any one of the three 〈100〉 axes of the fcc Pt parent particles could act as the tetragonal c axis of the L10 FePt superstructure and all three-variant ordered crystalline domains of the tetragonal L10 phase could exist in the small 10-nm-size FePt crystallites. The high magnetic coercivity of the film, with well-separated FePt particles, can be attributed to the ordering (L10) as well as the oriented nature of the FePt crystallites.

    Original languageEnglish
    Pages (from-to)3686-3688
    Number of pages3
    JournalApplied Physics Letters
    Volume75
    Issue number23
    DOIs
    Publication statusPublished - 1999 Dec 6

    ASJC Scopus subject areas

    • Physics and Astronomy (miscellaneous)

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