Exchange coupling of ferromagnetic films across metallic and semiconducting interlayers

• Published in: Journal of physics. Condensed matter 2003-02, Vol.15 (5), p.S443-S450
• Main Authors: Bürgler, D E, Buchmeier, M, Cramm, S, Eisebitt, S, Gareev, R R, Grünberg, P, Jia, C L, Pohlmann, L L, Schreiber, R, Siegel, M, Qin, Y L, Zimina, A
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electrical and thermal conduction in crystalline metals and alloys; Electronic conduction in metals and alloys; Electronic transport in condensed matter; Exact sciences and technology; Fe and its alloys; Magnetic properties and materials; Physics; Studies of specific magnetic materials
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/15/5/301

Recent results obtained in our laboratories on interlayer exchange coupling of Fe films across interlayers of iron silicides, Fe1-xSix with x = 0.5-1, are reviewed. Samples are prepared by molecular beam epitaxy and characterized by means of low-energy electron diffraction and cross-sectional transmission electron microscopy. Coupling across interlayers of iron silicide with x #~ 0.5 is found to be oscillatory with a strength of the order of 1 mJ m-2, and across well ordered Si interlayers (nominally x = 1) the coupling is exponentially decaying. In the latter case the maximum coupling turns out to be surprisingly strong ( > 6 mJ m-2), in particular considering the fact that the electrical resistivity is found to be large. Current-voltage curves for currents across the interlayers are characteristic of electron tunnelling. Soft-x-ray emission and near-edge x-ray absorption spectroscopy further support a semiconducting nature for the nominally pure Si interlayers.