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Experimental evidence of s-wave superconductivity in bulk CaC$_{6}$

G. Lamura·M. Aurino·G. Cifariello·E. Di Gennaro·A. Andreone·N. Emery·C. Herold·J. -F. Mareche·P. Lagrange
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Abstract

The temperature dependence of the in-plane magnetic penetration depth, $λ_{ab}(T)$, has been measured in a c-axis oriented polycrystalline CaC$_{6}$ bulk sample using a high-resolution mutual inductance technique. A clear exponential behavior of $λ_{ab}(T)$ has been observed at low temperatures, strongly suggesting isotropic s-wave pairing. Data fit using the standard BCS theory yields $λ_{ab}(0)=(720\pm 80)$ Angstroem and $Δ(0)=(1.79\pm 0.08)$ meV. The ratio $2Δ(0)/k_{_B}T_{c}=(3.6\pm 0.2)$ gives indication for a conventional weakly coupled superconductor.

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G. Lamura, M. Aurino, G. Cifariello, E. Di Gennaro, A. Andreone, N. Emery, C. Herold, J. -F. Mareche, P. Lagrange. 2006-01-16. Experimental evidence of s-wave superconductivity in bulk CaC$_{6}$. https://doi.org/10.1103/physrevlett.96.107008

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