Regensburg 2004 – wissenschaftliches Programm

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MA: Magnetismus

MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)

MA 13.27: Poster

Dienstag, 9. März 2004, 15:00–19:00, Bereich A

Extraordinary magnetoresistance effect in a ferromagnetic and half-metallic double perovskite — •Petra Majewski, Stephan Geprägs, Mitja Schonecke, Jan B. Philipp, Andreas Erb, Matthias Opel, Lambert Alff, and Rudolf Gross — Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meißner-Str. 8, 85748 Garching

The EMR (extraordinary magnetoresistance) effect, which was recently shown at low magnetic fields in semiconductor-metal hybrid structures, can be understood in terms of a magnetic field dependent deflection of current around the highly conducting metal. The interesting point is that a large positive magnetoresistance effect can be achieved in a non-magnetic system.

Here, we report on novel magnetoresistance effects in a ferromagnetic, half-metallic material, namely the double perovskite Sr₂CrWO₆, grown on conducting Nb doped SrTiO₃ as well as on undoped SrTiO₃ substrates. The high quality Sr₂CrWO₆ films were grown by UHV laser-MBE with the growth process monitored by an in-situ RHEED system. The sample surfaces were examined in-situ by AFM, and the crystalline properties were determined by x-ray diffraction. Magnetotransport and magnetic properties have been measured between 4 and 300 K at various applied fields. We show that the described system is of interest to study the influence of ferromagnetism on the EMR effect.