Regensburg 2002 – wissenschaftliches Programm
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MA: Magnetismus
MA 20: Exchange Bias und Coupling
MA 20.8: Vortrag
Freitag, 15. März 2002, 12:15–12:30, H10
Studies of strongly coupled epitaxial Fe(001)/Al/Fe trilayers by Brillouin Light Scattering. — •Matthias Buchmeier, Bijoy Kuanr, Rashid Gareev, Daniel Bürgler, and Peter Grünberg — Institut für Festkörperforschung, Forschungszentrum Jülich
The interlayer exchange coupling of Fe(50Å)/Al/Fe(70Å) wedge type epitaxial samples has been investigated by Brillouin Light Scattering (BLS). By fitting the field dependence of the frequency of excited magnons we are able to separate bilinear (J1) and biquadratic (J2) contributions to the interlayer exchange coupling. We find a nonoscillatory behavior of the coupling versus spacer thickness. The maximum total coupling strength (J1 + J2) at an interlayer thickness of 6Å is about −3mJ/m2 which is among the largest values observed sofar. With increasing interlayer thickness the biquadratic coupling contribution decreases more quickly than the intrinsic bilinear part, which is present at least until 20Å. However, J2 dominates to the left of the maxima at small interlayer thickness until it is overcome by pinhole-induced ferromagnetic coupling below 4Å. This suggests that the biquadratic coupling arises from the competition between pinhole-induced ferromagnetic and bilinear antiferromagnetic coupling.