Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 14: Poster: Schichten(1-31), Spinabh.Trsp.(32-47), Exch.Bias(48-54), Spindyn.(55-64), Mikromag.(65-76), Partikel(77-88), Oflmag.(89-92), Spinelektr.(93-98), Elektr.Theo.(99-103), Mikromag+PhasÜ+Aniso.(104-122), MagnMat.(123-134), Messm+Mol-Mag.(135-139), Kondo(140-151)

MA 14.46: Poster

Dienstag, 25. März 2003, 15:15–19:15, Zelt

The double perovskites A₂CrWO₆: Influence of the alcaline earth ions and doping on the Curie temperature — •Jan Boris Philipp, Daniel Reisinger, Mitja Schonecke, Matthias Opel, Achim Marx, Lambert Alff, Andreas Erb, and Rudolf Gross — Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meissner Str. 8, D-85748 Garching, Germany

Double perovskites of the type A₂CrWO₆ with A₂=Ba₂, Sr₂, SrCa und Ca₂ with and without La-doping on the A-site have been prepared. These materials are promising for applications in spin electronics due to their high Curie temperature and large spin polarization. They have been characterized by differential thermal analysis and x-ray diffraction. A systematic change in the size of the pseudo cubic unit cell goes along with a change of the Curie temperature, which varies between 420 K and 140 K. For polycrystalline material the temperature dependence of the resistivity is semiconducting due to the grain boundaries and a large negative MR-effect (>100%) at 5 K is observed [1]. La - doping systematically decreases the Curie temperature. Thin Films, which were grown by pulsed laser deposition, have high crystalline quality and atomically flat surface.

[1] J. B. Philipp, D. Reisinger, M. Schonecke, A. Marx, A. Erb, L. Alff, R. Gross, and J.Klein, Appl. Phys. Lett. 79, 3654 (2001)