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AM: Magnetismus
AM 18: Postersitzung Fürstenberghaus
AM 18.13: Poster
Mittwoch, 19. März 1997, 14:30–17:30, F"u
Giant Magnetoresistance in Antiferromagnetically Coupled Epitaxial FexCo1−x/Cr/FexCo1−x Trilayers — •Ch. Yu, K. Theis-Bröhl, Th. Zeidler, K. Westerholt, and H. Zabel — Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum
Epitaxial trilayers Fe1−xCox/Cr/Fe1−xCox(100) with x
in the concentration range 0≤x≤0.2 and a wedge shaped Cr interlayer of variable
thickness dCr were prepared using MBE-growth on sapphire (1102).
The exchange coupling was
characterized by measuring magnetic hysteresis loops via MOKE.
For the pure Fe/Cr/Fe trilayer we observe a maximum GMR effect of about
5% in the range of antiferromagnetic coupling with dCr=9Å.
With increasing Co concentration the amplitude of the GRM effect decreases
rapidly, reaching only a maximum value of 0.8% for the trilayer with a Co
concentration x=0.2. Simultanueosly, the temperature dependence of the GMR
changes qualitatively. The sensitivity of the GMR amplitude for a small
change of alloy concentration is attributed to a band filling of the
majority spin band combined with a strong spin dependent potential
scattering at the interface.
This work was supported by the DFG (SFB-166). One of us (Ch.Yu) gratefully
acknowledges a Humboldt fellowship.