Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 28: Transport - Poster Session

TT 28.41: Poster

Donnerstag, 29. März 2007, 14:00–17:45, Poster A

Ballistic magnetoresistance in Ni nanocontacts — •Steven Walczak, Michael Czerner, and Ingrid Mertig — Institute of Physics, Martin Luther University Halle-Wittenberg, Germany

During the last years the ballistic magnetoresistance of nickel (Ni) single-atom contacts has been measured in various of experiments. Recently, Sullivan et al. [1] reported about extraordinary large magnetoresistance in Ni nanocontacts. These experimental observations are still in contradiction to other experimental [2] and theoretical results in the coherent limit of transport [3].

Ab initio calculations of the electronic structure and transport properties of magnetic nanocontacts of Ni will be presented. The electronic structure of these nanocontacts is calculated self-consistently in the framework of the density functional theory by means of the Korringa-Kohn-Rostoker method. The transport properties are described in the linear response regime based on the Landauer approach in the formulation of Baranger and Stone [4].

This contribution aims to explain the change of the conductance values in dependence on strain and compression for a single-atom contact, the influence of the symmetry for small Ni clusters, and the effect of an external magnetic field on a magnetic Ni particle in the contact region.

[1] M. R. Sullivan et al., Phys. Rev. B 71, 024412 (2005)

[2] M. Viret et al., Phys. Rev. B 66, 220401(R) (2002)

[3] A. Bagrets et al., cond-mat/0510073 (2005)

[4] H. U. Baranger and A. D. Stone, Phys. Rev. B 40, 8169 (1989)