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Point-contact Andreev reflection in ferromagnet/superconductor ballistic nanojunctions

Taddei, F. and Sanvito, S. and Lambert, C. J. (2005) Point-contact Andreev reflection in ferromagnet/superconductor ballistic nanojunctions. Journal of Computational and Theoretical Nanoscience, 2 (1). pp. 132-137.

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Abstract

A critical analysis of point-contact Andreev reflection (PCAR) in ferromagnet/superconductor ballistic junctions is presented, based on tight-binding Hamiltonians with s, p and d orbitals and material-specific parameters. By accurately modeling the band structure of the bulk materials, we show that to reproduce the measured differential conductance of Cu/Pb and Co/Pb nanocontacts(1,2) one needs a detailed understanding of interface parameters which goes beyond simple averages of bulk matrix elements. As an example of how such a modification of surface parameters can affect spin-polarized transport, we explore the effect of an enhancement of the surface magnetization and show that this can significantly improve agreement with experiment. We also demonstrate that in general the spin polarization P of the junction may be different from the bulk polarization 15 of the magnetic metal used. For bulk Co we find (P) over bar = -0.4, whereas for the Co/Pb interface P = +0.4 and for the Co/Ir interface P = -0.01.

Item Type: Article
Journal or Publication Title: Journal of Computational and Theoretical Nanoscience
Uncontrolled Keywords: Nanojunctions ; Ferromagnets ; Superconductors ; Andreev Reflection
Subjects: Q Science > QC Physics
Departments: Faculty of Science and Technology > Physics
ID Code: 564
Deposited By: Prof Colin J. Lambert
Deposited On: 22 Jun 2007
Refereed?: Yes
Published?: Published
Last Modified: 17 Apr 2013 15:39
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/564

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