Non-exponential London penetration depth in Ba$_{1-}$K$_{x}$Fe$_{2}$As$_{2}$ single crystals

C. Martin; R. T. Gordon; M. A. Tanatar; H. Kim; N. Ni; S. L. Bud'ko; P. C. Canfield; H. Luo; H. H. Wen; Z. Wang; A. B. Vorontsov; V. G. Kogan; R. Prozorov

doi:10.1103/PhysRevB.80.020501

paper

Non-exponential London penetration depth in Ba $_{1 -}$ K $_{x}$ Fe $_{2}$ As $_{2}$ single crystals

arXiv:0902.1804 · doi:10.1103/PhysRevB.80.020501

Abstract

We have studied the in- and out-of-plane magnetic penetration depths in the hole- doped iron based superconductor Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ ( $T_{c} \approx$ 30K). The study was performed on single crystals grown from different fluxes and we find that the results are nearly the same. The in-plane London penetration depth $λ_{ab}$ does not show exponential saturation at low temperature, as would be expected from a fully gapped superconductor. Instead, $λ_{ab} (T)$ shows a power-law behavior, $λ \propto T^{n}$ ( $n \approx 2$ ), down to $T \approx 0.02 T_{c}$ , similar to the electron doped Ba(Fe $_{1 - x}$ Co $_{x}$ ) $_{2}$ As $_{2}$ . The penetration depth anisotropy $γ_{λ} = λ_{c} (T) / λ_{ab} (T)$ increases upon cooling, opposite to the trend observed in the anisotropy of the upper critical field, $γ_{ξ} = H_{c 2}^{⊥ c} (0) / H_{c 2}^{∥ c} (0)$ . These are universal characteristics of both the electron and hole doped 122 systems, suggesting unconventional superconductivity. The behavior of the in-plane superfluid density $ρ_{ab} (T)$ is discussed in light of existing theoretical models proposed for the iron pnictides superconductors.

Non-exponential London penetration depth in Ba $_{1 -}$ K $_{x}$ Fe $_{2}$ As $_{2}$ single crystals

Abstract

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Non-exponential London penetration depth in Ba1−​Kx​Fe2​As2​ single crystals

Abstract

References in corpus (29)

Cited by in corpus (50)

Non-exponential London penetration depth in Ba $_{1 -}$ K $_{x}$ Fe $_{2}$ As $_{2}$ single crystals