Unconventional superconductivity of NdFeAsO0.82F0.18 indicated by the low temperature dependence of the lower critical field Hc1

Abstract

We measured the initial M-H curves for a sample of the newly discovered superconductor NdFeAsO0.82Fe0.18, which had a critical temperature, Tc, of 51 K, and was fabricated at the high pressure of 6 GPa. The lower critical field, Hc1, was extracted from the deviation point of the Meissner linearity in the M-H curves, which show linear temperature dependence in the low temperature region down to 5 K. The Hc1(T) indicates no s-wave superconductivity, but rather an unconventional superconductivity with a nodal gap structure. Furthermore, the linearity of Hc1 at low temperature does not hold at high temperature, but shows other characteristics, indicating that this superconductor might have multi-gap features. Based on the low temperature nodal gap structure, we estimate that the maximum gap magnitude delta 0 = (1.6+- 0.2) kBTc.

8 pages, 3 figures

References in corpus (4)

• Superconductivity in iron-based F-doped layered quaternary compound Nd[O1-xFx]FeAs
• Very High Field Two-Band Superconductivity in LaFeAsO_0.89F_0.11
• The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
• Superconductivity at 53.5 K in GdFeAsO1-delta

Cited by in corpus (5)

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• Nodeless superconductivity in the presence of spin-density wave in pnictide superconductors: The case of BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Constraints Imposed by Symmetry on Pairing Operators for the Pnictides