Thermal stability of ultrasoft Fe-Zr-N films

NG Chechenin*, A van Veen, H Schut, AR Chezan, D Boerma, T Vystavel, JTM De Hosson

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    10 Citations (Scopus)

    Abstract

    The thermal stability of nanocrystalline ultrasoft magnetic (Fe98Zr2)(1-x)N-x films with x = 0.10-0.25 was studied using thermal desorption spectrometry, positron beam analysis and high resolution transmission electron microscopy. The results demonstrate that grain growth during the heat treatment is accompanied by an increase of the free volume and nitrogen relocation and desorption. All these phenomena can drastically degrade the ultrasoft magnetic properties. The nitrogen desorption has already started at temperatures around 400 K. Nevertheless, most of the nitrogen leaves the sample at a temperature above 800 K. We found that nitrogen out-diffusion is significantly retarded compared with the prediction of the diffusion in bulk alpha-Fe. A qualitative model is proposed in which the nitrogen out-diffusion in nanocrystalline material is retarded by trapping at immobile defects, namely Zr atoms, and also by voids at grain boundaries. From a certain temperature, nitrogen migrates from the interior of the nanograins to the nanovoids at the grain boundaries and the out-diffusion to the outer surface is controlled by transport between the voids.

    (Some figures in this article are in colour only in the electronic version).

    Original languageEnglish
    Article numberPII S0953-8984(03)64337-7
    Pages (from-to)7663-7674
    Number of pages12
    JournalJournal of Physics-Condensed Matter
    Volume15
    Issue number45
    DOIs
    Publication statusPublished - 31-Oct-2003

    Keywords

    • SOFT-MAGNETIC PROPERTIES
    • IRON SURFACES
    • THIN-FILMS
    • NITROGEN
    • MICROSTRUCTURE
    • DESORPTION
    • EVOLUTION
    • RIPPLE

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