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arXiv · 1101.5363

Superfluid density measurements of Ba(CoxFe1-x)2As2 films near optimal doping

Jie Yong·S. Lee·J. Jiang·C. W. Bark·J. D. Weiss·E. E. Hellstrom·D. C. Larbalestier·C. B. Eom·T. R. Lemberger
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Abstract

We report the first direct measurements of superfluid density, ns(T) \propto λ-2(T), in films of Fe-pnictide superconductors. The magnetic penetration depth, λ(0), in our epitaxial, single-crystal Ba(CoxFe1-x)2As2 films near optimal doping (x=0.08) is 350 nm to 430 nm, comparable to bulk single crystals. The T-dependence of λ-2 indicates a small s-wave gap, 2Δ(0)/kBTc = 2.2 \pm 0.1. In detail, λ has power-law behavior at low T: λ(T)/λ(0) - 1 \approx 0.60*(T/Tc)2.5\pm0.1. The small gap, together with power-law behavior at low T, suggests strong intraband scattering on the larger-gap Fermi surface and significant interband scattering between large-gap and small-gap Fermi surfaces.

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Jie Yong, S. Lee, J. Jiang, C. W. Bark, J. D. Weiss, E. E. Hellstrom, D. C. Larbalestier, C. B. Eom, T. R. Lemberger. 2011-01-27. Superfluid density measurements of Ba(CoxFe1-x)2As2 films near optimal doping. https://doi.org/10.1103/physrevb.83.104510

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