Regensburg 2002 – wissenschaftliches Programm

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MA: Magnetismus

MA 6: Spinabhängige Transportphänomene I

MA 6.11: Vortrag

Montag, 11. März 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.