Superconducting energy gap in MgCNi3 single crystals

J. Kacmarcík (1) , Z. Pribulova (1) , P. Szabo (1) , P. Samuely (1) , C. Marcenat (2) , Thierry Klein (3) , D.J. Jang (4) , H.G. Lee (4) , H.S. Lee (4) , S.I. Lee (4)

1 CLTP IEP - Centre of Low Temperature Physics
2 SPSMS - UMR 9001 - Service de Physique Statistique, Magnétisme et Supraconductivité
3 NEEL - MagSup - Magnétisme et Supraconductivité
4 NVCRICS

Even though MgCNi3 contains large molar volume of magnetic Ni atoms it clearly shows superconductivity. The origin of superconductivity in this material has not yet been clarified. There is a lot of discrepancy in experimental results and physical interpretation where even unconventional pairing or a two-band model have been proposed for the system. All that is based on results obtained on polycrystalline samples. Here we present the first point-contact spectroscopy and ac-calorimetry measurements on the MgCNi3 single crystals of very good quality. Measurements have been performed in the temperature range from 1.5 to 10 K and in magnetic fields up to 8 T. The temperature dependence of the energy gap of the system is presented and compared to the BCS model.

Domaines: Supraconductivité [cond-mat.supr-con]

J. Kacmarcík, Z. Pribulova, P. Szabo, P. Samuely, C. Marcenat, et al.. Superconducting energy gap in MgCNi3 single crystals. Journal of Physics and Chemistry of Solids, 2008, 69 (12), pp.3011. ⟨10.1016/j.jpcs.2008.06.009⟩. ⟨hal-00957680⟩