Regensburg 2004 – scientific programme
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MA: Magnetismus
MA 27: Spinabh
ängiger Transport II
MA 27.10: Talk
Thursday, March 11, 2004, 17:30–17:45, H22
Theoretical Investigations on Spin-Dependent Electronic Transport in Magnetic Tunnel Junctions — •Voicu Popescu1, Hubert Ebert1, Rudolf Zeller2, and Peter H. Dederichs2 — 1Department Chemie/Physikalische Chemie, University of Munich, Butenandtstr. 5-13, 81377 Munich, Germany — 2Inst. für Festkörperforschung,Forschungszentrum Jülich, Postfach 1913, D-52425 Jülich, Germany
Spin-dependent transport between two ferromagnetic electrodes separated by either an insulator or a semiconductor has received a lot of interest in the last years due to its potential technological applications. The impressive theoretical work done in this field, however, still lacks a fair quantitative agreement with the experimental results.
Some possible sources leading to the existing discrepancies have been investigated and will be presented and discussed. For this we have applied a Tight-Binding Spin-Polarised Relativistic Multiple Scattering Theory (TB-SPR-KKR) method in calculating the electronic structure of an Fe/GaAs/Fe magnetic tunnel junction. Interface relaxation, interface inderdiffusion by means of a Coherent Potential Approximation (CPA) and Spin-Orbit Coupling (SOC) have been accounted for.
The transport properties are calculated according to the Landauer-Büttiker formalism on a relativistic level. Model calculations allowed us to investigate in detail the spin-flip contribution to the conductance, at the Fe/GaAs interface and/or within the semiconductor spacer.