The linear and nonlinear response to a microwave electromagnetic field of two c-axis oriented polycrystalline samples of the newly discovered superconductor CaC6 (Tc = 11.5 K) is studied in the superconducting state down to 2 K. The surface resistance Rs and the third order intermodulation distortion, arising from a two-tone excitation, have been measured as a function of temperature and microwave circulating power. Experiments are carried out using a dielectrically loaded copper cavity operating at 7 GHz in a "hot finger" configuration. The results confirm recent experimental findings that CaC6 behaves as a weakly-coupled, fully gapped, superconductor. The weak power dependence of Rs encourages a further investigation of this novel superconductor as a possible alternative to Nb in specific microwave applications.
@article{arxiv.cond-mat/0610497,
title = {Linear and nonlinear electrodynamic response of bulk CaC6 in the microwave regime},
author = {A. Andreone and G. Cifariello and E. Di Gennaro and G. Lamura and N. Emery and C. Herold and J. F. Mareche and P. Lagrange},
journal= {arXiv preprint arXiv:cond-mat/0610497},
year = {2009}
}