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MA: Magnetismus
MA 6: Spinabhängige Transportphänomene I
MA 6.11: Talk
Monday, March 11, 2002, 17:45–18:00, H22
Magnetization and magnetotransport of superlattices based on the Heusler compound Co2MnGe — •Andre Bergmann, Uwe Geiersbach, and Kurt Westerholt — Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum
We report magnetization and magnetotransport measurements of superlattices
combining the Heusler alloy Co2MnGe with V, Au and Cr. The Heusler
phase Co2MnGe is interesting since following energy band structure
calculations it should have 100% spin polarization at the Fermi energy.
Due to interface alloying the ferromagnetic saturation magnetization of
Co2MnGe is reduced in the superlattices. The magnetic disorder at the
interface is responsible for the large isotropic negative magnetoresistance
which can be observed up to magnetic fields of 5 T. Additionally
compositional fluctuations at the interfaces lead to magnetic frustration
and an exchange bias effect in low temperature magnetic hysteresis loops.
First attempts to build spin valve elements based on the Co2MnGe alloy
are reported.
Acknowledgement
The authors thank the DFG for
support of this work within the SFB 491.