Experimental evidence of s-wave superconductivity in bulk CaC6.
The temperature dependence of the in-plane magnetic penetration depth, lambda(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 lambda(ab)(T) has been observed at low temperatures, strongly suggesting isotropic s-wave pairing. Data fit using the standard BCS theory yields lambda(ab)(0) = (720 +/- 80) A and delta(0) = (1.79 +/- 0.08) meV. The ratio 2delta(0)/k(B)T(c) = (3.6 +/- 0.2) gives indication for a weakly coupled superconductor.
Lamura
G
G
CNR-INFM Coherentia and Department of Physics, University of Naples, Federico II, I-80125, Napoli, Italy. gianrico.lamura@na.infn.it
Aurino
M
M
Cifariello
G
G
Di Gennaro
E
E
Andreone
A
A
Emery
N
N
Hérold
C
C
Marêché
J-F
JF
Lagrange
P
P