Magnetic penetration depth of single crystal SmFeAsO_{1-x}F_y: a fully gapped superconducting state

Abstract

We report measurements of the in-plane magnetic penetration depth $\lambda$ in single crystals of SmFeAsO${}_{1-x}$F${}_y$ ($x\simeq y\simeq 0.2$) with $T_c\simeq 45$ K. We find that at low temperature $\lambda$ has an exponential temperature dependence which suggests that the Fermi surface is fully gapped. The magnitude of the minimum energy gap, ${\Delta }_1=1.1\pm 0.1k_B{T}_c$ at T=0 K, is significantly smaller than the BCS weak-coupling value suggesting that the gap is either strongly anisotropic or varies significantly between the different Fermi surface sheets. Our data fits well a two gap model with an additional larger gap of magnitude ${\Delta }_2=1.8\pm 0.2k_B{T}_c$ which is associated with $\sim 80$% of the total superfluid density.

4 pages with figures

References in corpus (13)

• LaFeAsO${}_{1-x}$F${}_x$: A low carrier density superconductor near itinerant magnetism
• Pairing Symmetry in a Two-Orbital Exchange Coupling Model of Oxypnictides
• The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
• Microwave Penetration Depth and Quasiparticle Conductivity in PrFeAsO_1-y Single Crystals : Evidence for a Full-Gap Superconductor
• Single crystal of superconducting SmFeAsO1-xFy grown at high pressure
• Penetration depth study of superconducting gap structure of 2\textit{H}-NbSe${}_2$
• Lifting of nodes by disorder in extended-$s$ state superconductors: application to ferropnictides
• Coexistence of magnetic fluctuations and superconductivity in the pnictide high temperature superconductor SmFeAsO${}_{1-x}$F${}_x$ measured by muon spin rotation
• Muon-spin rotation studies of SmFeAsO_0.85 and NdFeAsO_0.85 superconductors
• The London penetration depth in single crystals of Ba(Fe_{1-x}Co_x)_2As_2 at various doping levels
• Anisotropy of superconducting single crystal SmFeAsO_(0.8)F_(0.2) studied by torque magnetometry
• Evidence for two distinct anisotropies in the oxypnictide superconductors SmFeAsO_(0.8)F_(0.2) and NdFeAsO_(0.8)F_(0.2)
• Comment on " Low-Lying Quasiparticle States and Hidden Collective Charge Instabilities in Parent Cobaltate Superconductors"

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