Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 30: Spin-Electronics II
MA 30.2: Vortrag
Donnerstag, 30. März 2006, 15:30–15:45, HSZ 103
Spin-dependent tunneling through antiferromagnets: Mn/Fe(001) — •Peter Bose1, Jürgen Henk2, Arthur Ernst2, Ingrid Mertig1, and Patrick Bruno2 — 1Martin-Luther-Universität, FB Physik, FG Theoretische Physik, 06099 Halle/S., Germany — 2MPI für Mikrostrukturphysik, Abteilung Theorie, 06120 Halle/S., Germany
The size of the tunnel magnetoresistance (TMR) of a magnetic tunnel junction (MTJ) which includes an antiferromagnet (AFM) film is a priori not clear. On one hand, a large TMR can be expected due to the large spin polarization in the leads. On the other hand, the TMR is determined essentially by interface properties, suggesting a small TMR due to the interfaces of the antiferromagnet. Recent spin-resolved scanning tunneling microscopy (SR-STM) experiments [1] proved that the latter is true for layer-wise AFM Mn films on Fe(001) [2], hence stressing the importance of interface properties.
While model calculations corroborate the experimental findings [1], there appears need for sophisticated first-principles tunneling calculations, the latter being reported on in this contribution. The spin-dependent conductance of Fe/Mn/vacuum/Fe MTJs is computed within Landauer-Büttiker theory applying multiple-scattering theory (layer-KKR). By this means, the origin of the experimentally observed TMR is unequivocally determined. Further, the role of surfaces states which provide a contrast mechanism in SR-STM is investigated.
[1] U. Schlickum et al, submitted to Phys. Rev. Lett.
[2] A. Ernst, J. Henk, R. K. Thapa, J. Phys.: Cond. Matt. 17 (2005), 3269.