Theoretical study of the conductance of ferromagnetic atomic-sized contacts

M. Häfner, J. K. Viljas, D. Frustaglia, F. Pauly, M. Dreher, P. Nielaba, and J. C. Cuevas
Phys. Rev. B 77, 104409 – Published 10 March 2008

Abstract

In this work, we study theoretically the conductance of atomic contacts of the ferromagnetic 3d materials Fe, Co, and Ni. For this purpose, we employ a tight-binding model and we focus on the analysis of ideal contact geometries. In agreement with previous theoretical results, the 3d bands of these transition metals play the key role in the electrical conduction of atomic contacts. As a consequence, in the contact regime, there are partially open conductance channels and the conductance of the last plateau is typically above G0=2e2h. Furthermore, in this regime, there is no complete spin polarization of the current (i.e., both spin bands contribute to transport) and the amplitude of the conductance as well as its spin polarization are very sensitive to disorder in the contact geometry. Finally, we find that in the tunneling regime, a high spin polarization of the current can be achieved.

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  • Received 5 February 2008

DOI:https://doi.org/10.1103/PhysRevB.77.104409

©2008 American Physical Society

Authors & Affiliations

M. Häfner1,2, J. K. Viljas1,3, D. Frustaglia4, F. Pauly1,3, M. Dreher5, P. Nielaba5, and J. C. Cuevas2,1,3

  • 1Institut für Theoretische Festkörperphysik, Universität Karlsruhe, D-76128 Karlsruhe, Germany
  • 2Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
  • 3Institut für Nanotechnologie, Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany
  • 4NEST-CNR-INFM and Scuola Normale Superiore, I-56126 Pisa, Italy
  • 5Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany

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Issue

Vol. 77, Iss. 10 — 1 March 2008

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