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AM: Magnetismus
AM 10: Dünne Schichten I
AM 10.10: Vortrag
Mittwoch, 28. März 2001, 16:15–16:30, S 5.2
Magnetic Exchange Coupling in FeCr/Cr Superlattices — •Andreas Schreyer1, Ralf Siebrecht2, Till Schmitte1, Katharina Theis-Bröhl1, and Hartmut Zabel1 — 1Institut für Experimentalphysik (Festkörperphysik), Ruhr-Universität Bochum, 44780 Bochum — 2Institut Laue Langevin, F-38042 Grenoble, Frankreich
Based on previous studies of Fe/Cr superlattices [1] we have replaced the Fe layers by an Fex−1Crx alloy in a wide concentration range x. Neutron reflectivity and MOKE measurements show that increasing x from zero to 0.8 reduces the Curie temperature TC to zero. Although a strong effect on the Néel temperature TN of the Cr interlayers is expected, neutron scattering data only indicate a drop of TN from 500 to 330 K at x= 0.8. The exchange coupling properties are dramatically modified compared to the Fe/Cr system. Whereas our Fe/Cr samples exhibited a strong non-collinear coupling mediated by frustrated spirals of antiferromagnetic Cr [1], the FeCr/Cr samples exhibit only strongly temperature dependent collinear ferro- or antiferromagnetic coupling. These results can be understood by considering the modification of the interface topology upon alloying.
[1] A. Schreyer et al., Phys. Rev. Lett. 79, 4914 (1997).