Possible Unconventional superconductivity in YCo$_{0.7}$C$_{2}$

Non-centrosymmetric superconductors as CePt$_{3}$Si [1,2] and sequicarbides (La,Y)$_{2}$C$_{3}$ [3] are remarkable examples of unusual properties displayed associated to unconventional pairing due to an antisymmetric spin-orbit coupling. Another interesting case is the family of compounds belonging to the CeNiC$_{2}$ type structure, in which more than thirty stable compounds have found to crystallize in this structure. Here we report magnetization, resistivity, and heat capacity measurements on poly-crystalline samples of non-centrosymmetric YCo$_{0.7}$C$_{2}$, showing clear evidence of bulk superconductivity with a critical temperature of T$_{c}=4$ K. Interestingly the specific heat of the superconducting state deviates from conventional exponential temperature dependence, which is suggestive of possible unconventional superconducting behavior in YCo$_{0.7}$C$_{2}$, similar to that seen in the isostructural and isoelectronic superconductor LaNiC$_{2}$ [4]. Besides, these results strongly suggest that this material is a strong candidate of multiband superconductivity. \\ References: [1] E. Bauer, G. Hilscher, H. Michor, C. Paul and P. Rogl, Phys. Rev. Lett. 92 (2004) 027003.