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arXiv · 1302.5326

Experimental study of intrinsic multiple Andreev reflections effect in GdO(F)FeAs superconductor array junctions

T. E. Kuzmicheva·S. A. Kuzmichev·M. G. Mikheev·Ya. G. Ponomarev·S. N. Tchesnokov·Yu. F. Eltsev·V. M. Pudalov·A. V. Sadakov·A. S. Usoltsev·E. P. Khlybov·L. F. Kulikova
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Abstract

We report the first observation of the intrinsic multiple Andreev reflections effect (IMARE) in S-n-S-...-S-arrays (S = superconductor, n = normal metal) formed by "break-junction" technique in GdO(F)FeAs superconductor (Tc = 48 - 53 K). We show that superconducting gap peculiarities at dI/dV-spectra sharpen dramatically in the arrays as compared with that in the single-contact spectra; this enables to improve significantly accuracy of the bulk superconducting parameters determination. Using IMARE, we determined the large and the small gap values Δ_L = 11 +- 1.1 meV and Δ_S = 2.6 +- 0.4 meV. The BCS-ratio 2Δ_L/kTc^{local} = 5.0 - 5.9 > 3.52 (Tc^{local} is the contact area critical temperature) evidences for a strong electron-boson coupling. The results obtained agree well with our previous data by Andreev spectroscopy for single SnS-contacts.

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T. E. Kuzmicheva, S. A. Kuzmichev, M. G. Mikheev, Ya. G. Ponomarev, S. N. Tchesnokov, Yu. F. Eltsev, V. M. Pudalov, A. V. Sadakov, A. S. Usoltsev, E. P. Khlybov, L. F. Kulikova. 2013-02-21. Experimental study of intrinsic multiple Andreev reflections effect in GdO(F)FeAs superconductor array junctions. https://doi.org/10.1209/0295-5075%2F102%2F67006

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