Berlin 2018 – scientific programme

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MA: Fachverband Magnetismus

MA 2: Focus Session: Nanomagnetism in the x-ray spotlight

MA 2.7: Talk

Monday, March 12, 2018, 12:30–12:45, H 1012

Element-specific characterization of Co:FePt nanocomposite magnet films — •Fabrice Wilhelm¹, Veronique Dupuis², Damien Le Roy², Nora Dempsey³, and Andrei Rogalev¹ — ¹European Synchrotron Radiation Facility, Grenoble, France — ²Institut Lumière Matière, Villeurbanne, France — ³Institut Néel, Grenoble, France

Nanocomposite magnets consisting of a fine mixture of a hard magnetic phase and a high saturation magnetization phase are promising systems to overpass performances of the best permanent magnets. To achieve this aim, it is necessary to confine the soft magnetic phase in grains of typically less than 10nm [1]. Here we report on thorough study of Co:FePt nanocomposite where Co nanoclusters with size of 6 nm constitute the soft magnetic phase which is embedded in L10-FePt matrix. Standard structural (e.g. XRD, SEM, TEM) and magnetic (SQUID magnetometry, MFM) characterizations were complemented with X-ray natural linear dichroism (XLD) and X-ray magnetic circular dichoism (XMCD) spectroscopies at the K-edges of Fe and Co. XLD measurements confirmed that Co is embedded in FePt matrix. XMCD measurements in turn show that Co and Fe atoms are ferromagnetically coupled and that the Co:FePt nanocomposite behaves like a single magnetic phase.

Funding by the ANR-SHAMAN (ANR-16-CE09-0019) is acknowledged.

[1]Skomski R. and Coey J. M. D. Giant energy product in nanostructured two-phase magnets. Phys. Rev. B 48, 15812 (1993).