Regensburg 2002 – scientific programme
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MA: Magnetismus
MA 20: Exchange Bias und Coupling
MA 20.10: Talk
Friday, March 15, 2002, 12:45–13:00, H10
Antiferromagnetic interlayer exchange coupling in MBE-grown Fe/Fe1−xSix/Fe structures — •Rashid R. Gareev, Daniel E. Bürgler, Matthias Buchmeier, Reinert Schreiber, and Peter Grünberg — IFF, Forschungszentrum Jülich GmbH
Epitaxial Fe/Fe1−xSix/Fe (0.4 < x < 1) sandwiches with
wedge-shaped spacers are grown by molecular beam epitaxy.
Codeposition of Fe and Si at controlled atomic fluxes yields the
desired nominal Si content x. Metallic-type iron-silicide [1]
boundary layers (BL) are inserted at interfaces to suppress
interdiffusion. Well-defined LEED patterns indicate epitaxial growth
of the whole structure. The contributions of the bilinear and
biquadratic coupling terms to interlayer exchange coupling J are
determined from MOKE hysteresis loops and Brillouin light scattering.
The coupling strength drastically increases with Si content and
reaches values of |J|≈ 6 mJ/m2 for a nominally pure Si
spacer [2]. Inserting BL leads to a further increase of the
interlayer coupling exceeding 8 mJ/m2. This value is one of the
largest ever reported. The increase of the coupling strength is
accompanied by a shift of the coupling maximum to a smaller spacer
thickness. We conclude that inserting of BL suppresses pin-hole
formation and enables antiferromagnetic exchange coupling at a smaller
spacer thickness. Together with the exponential dependence of the
coupling on spacer thickness this results in even stronger coupling.
R.R. Gareev, D.E. Bürgler, D. Olligs, M. Buchmeier, R. Schreiber, P.
Grünberg, Phys. Rev. Lett. 87, 157202 (2001).
R.R. Gareev, D.E. Bürgler, M. Buchmeier, R. Schreiber, P.
Grünberg, J. Magn. Magn. Mater., in press (2001).