Josephson effect in S_{\rm F}XS_{\rm F} junctions

2002/05/15 by N. M. Chtchelkatchev, W. Belzig, C. Bruder
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.supr-con

paper · pdf · doi:10.1134/1.1503330

published as JETP Letters, Vol. 75(12), 2002, p. 646 [Pisma v Zhurnal Eksperimentalnoi i Teoreticheskoi Fiziki, Vol. 75(12), 2002, p. 772] · 5 pages, 5 figures

arxiv created 2002/05/15 · arxiv updated 2009/11/30

Abstract

We investigate the Josephson effect in S_{\rm F}XS_{\rm F} junctions, where S_{\rm F} is a superconducting material with a ferromagnetic exchange field, and X a weak link. The critical current I_c increases with the (antiparallel) exchange fields if the distribution of transmission eigenvalues of the X-layer has its maximum weight at small values. This exchange field enhancement of the supercurrent does not exist if X is a diffusive normal metal. At low temperatures, there is a correspondence between the critical current in an S_{\rm F}IS_{\rm F} junction with collinear orientations of the two exchange fields, and the AC supercurrent amplitude in an SIS tunnel junction. The difference of the exchange fields h₁-h₂ in an S_{\rm F}IS_{\rm F} junction corresponds to the potential difference V₁-V₂ in an SIS junction; i.e., the singularity in I_c [in an S_{\rm F}IS_{\rm F} junction] at |h₁-h₂|=Δ₁+Δ₂ is the analogue of the Riedel peak. We also discuss the AC Josephson effect in S_{\rm F}IS_{\rm F} junctions.

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