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 14.96: Poster
Dienstag, 25. März 2003, 15:15–19:15, Zelt
Spin polarisation estimated using manganite-semiconductor Schottky junctions — •Kathrin Dörr1,2, Guenole Jan1, Mike Coey1, Theresia Walter2, Karl-Hartmut Müller2, and Ludwig Schultz2 — 1SFI Lab, Physics Dep., Trinity College, Dublin 2, Ireland — 2IFW Dresden, Postfach 270116, 01171 Dresden, Germany
At present, all the methods able to determine the charge carrier spin polarisation of ferromagnetic metals are restricted in some way (to low temperatures or in energy resolution, e. g. Andreev reflection or spin-polarised photoemission spectroscopy). A novel and versatile method has been proposed based on the magnetic field dependence of the I-V characteristic of a metal-semiconductor Schottky barrier, which originates from the Zeeman shift of the Fermi level [1]. We apply this method to junctions of the half metal-like manganite La0.7Sr0.3MnO3 with the n-doped semiconductor Nb:SrTiO3. Epitaxial junctions have been prepared by pulsed laser deposition, varying the Nb doping rate of the SrTiO3(100) substrates (0.2 or 0.5 percent). The influence of the strain state of the LSMO films has been studied using junctions with as-deposited or strain-relaxed films. Measured I-V characteristics are typical of a Schottky barrier. The field dependence is discussed in terms of the magnetoresistance and the field effect on the Schottky barrier. [1] J. F. Gregg in: Spin Electronics, ed. M. Ziese and M. J. Thornton (Springer-Verlag, Berlin, Germany 2001), p.3-31