DOI: 10.1209/epl/i2001-00107-2


Europhys. Lett., 54 (3) , pp. 394-400 (2001)

Quantum spin fluctuations as a source of long-range proximity effects in diffusive ferromagnet-super conductor structures

A. Kadigrobov^{1, 2}, R. I. Shekhter¹ and M. Jonson<sup>1

1</sup>  Department of Applied Physics, Chalmers University of Technology and Göteborg University - SE-412 96 Göteborg, Sweden
²  B. I. Verkin Institute for Low Temperature Physics & Engineering National Academy of Science of Ukraine - 47 Lenin Ave. 310164 Kharkov, Ukraine

(Received 12 January 2001; accepted in final form 19 February 2001)

Abstract
We show that quantum spin fluctuations in inhomogeneous ferromagnets drastically affect the Andreev reflection of electrons and holes at a ferromagnet-superconductor interface. As a result, a strong long-range proximity effect appears, associated with electron-hole spin-triplet correlations and persisting on a length scale typical for non-magnetic materials, but anomalously large for ferromagnets.

PACS
74.50.+r - Proximity effects, weak links, tunneling phenomena, and Josephson effects.
74.80.Fp - Point contacts; SN and SNS junctions.
85.35.Ds - Quantum interference devices.


© EDP Sciences 2001

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