Point-contact study of the heavy-fermion superconductor CeCoIn5 Original Research Article

We have investigated the differential conductance spectra of the point contacts between the heavy-fermion superconductor CeCoIn5 and Pt. Many of them show a double-maximum structure that indicates the superconducting energy gap ΔΔ. The ΔΔ values derived using Blonder–Tinkham–Klapwijk model, however, varies from 0.47 to 0.77 meV, and yet they are within the scatter of the reported values. The evolution of ΔΔ below TcTc is slow as compared with that of BCS gap probably reflecting the unconventional superconductivity in CeCoIn5.