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Millimeter-wave study of London penetration depth temperature dependence in Ba(Fe(0.926)Co(0.074))(2)As(2) single crystal

TitleMillimeter-wave study of London penetration depth temperature dependence in Ba(Fe(0.926)Co(0.074))(2)As(2) single crystal
Publication TypeJournal Article
Year of Publication2011
AuthorsBarannik AA, Cherpak NT, Ni N, Tanatar MA, Vitusevich SA, Skresanov VN, Canfield PC, Prozorov R, Glamazdin VV, Torokhtii KI
Journal TitleLow Temperature Physics
Volume37
Pages725-728
Date Published08
Type of ArticleLetter
ISBN Number1063-777X
Accession NumberWOS:000297935800012
Keywordssuperconductors
Abstract

In-plane surface Ka-band microwave impedance of optimally doped single crystals of the Fe-based superconductor Ba(Fe(0.926)Co(0.074))(2)As(2) (T(c) = 22.8 K) was measured. Sensitive sapphire disk quasi-optical resonator with high-T(c) cuprate conducting endplates was developed specially for Fe-pnictide superconductors. It allowed finding temperature variation of London penetration depth in a form of power law, namely Delta lambda(T) similar to T(n) with n = 2.8 from low temperatures up to at least 0.6T(c) consisted with radio-frequency measurements. This exponent points towards nodeless state with pairbreaking scattering, which can support one of the extended s-pairing symmetries. The dependence lambda(T) at low temperatures is well described by one superconducting small-gap (Delta congruent to 0.75 in kT(c) units, where k is Boltzmann coefficient) exponential dependence. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3660321]
DOI10.1063/1.3660321
Alternate JournalLow Temp. Phys.