Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/102407
Title: Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap
Authors: Abdel-Hafiez, M.
Pereira, P. J.
Kuzmichev, S. A.
Kuzmicheva, T. E.
Pudalov, V. M.
Harnagea, L.
Kordyuk, A. A.
Silhanek, A. V.
Moshchalkov, V. V.
Shen, B.
Wen, H. -H.
Vasiliev, A. N.
Chen, X. -J.
Issue Date: 2014
Citation: Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap / M. Abdel-Hafiez, P. J. Pereira, S. A. Kuzmichev, et al. — DOI 10.1103/PhysRevB.90.054524 // Physical Review B - Condensed Matter and Materials Physics. — 2014. — Vol. 90. — Iss. 5. — 054524.
Abstract: Using two experimental techniques, we studied single crystals of the 122-FeAs family with almost the same critical temperature, Tc. We investigated the temperature dependence of the lower critical field Hc1(T) of a Ca0.32Na0.68Fe2As2 (Tc≈34K) single crystal under static magnetic fields H parallel to the c axis. The temperature dependence of the London penetration depth can be described equally well either by a single anisotropic s-wave-like gap or by a two-gap model, while a d-wave approach cannot be used to fit the London penetration depth data. Intrinsic multiple Andreev reflection effect spectroscopy was used to detect bulk gap values in single crystals of the intimate compound Ba0.65K0.35Fe2As2, with the same Tc. We estimated the range of the large gap value ΔL=6-8 meV (depending on small variation of Tc) and its a k space anisotropy of about 30%, and the small gap ΔS≈1. 7±0.3 meV. This clearly indicates that the gap structure of our investigated systems more likely corresponds to a nodeless s-wave two gaps. © 2014 American Physical Society.
URI: http://hdl.handle.net/10995/102407
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 84921793221
PURE ID: 372924
47492f78-ee77-4936-a59b-d5cada660200
ISSN: 10980121
DOI: 10.1103/PhysRevB.90.054524
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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