Superconducting Properties of CdCNi3

CdCNi 3 is a newly synthesized superconductor with T c =2.5–3.2 K. The crystal has the same perovskite-type structure as MgCNi 3 but the lattice constant is ∼1% larger than that of MgCNi 3 . For this material, superconducting parameters, lower critical field H c1 (0), upper critical field H c2 (0), coherence length ξ(0), penetration depth λ(0), Ginzburg–Landau parameter κ(0), electronic specific heat coefficient γ, and Debye temperature Θ D have been experimentally determined. Also, full-potential augmented plane wave band calculation has been performed for CdCNi 3 . From experimental and band calculation results, it has been suggested that the smaller density of states at the Fermi energy and enhanced ferromagnetic correlation reduce the T c of CdCNi 3 , compared with that of MgCNi 3 .