Point-contact study of the heavy-fermion superconductor CeCoIn5

Abstract We have investigated the differential conductance spectra of the point contacts between the heavy-fermion superconductor CeCoIn 5 and Pt. Many of them show a double-maximum structure that indicates the superconducting energy gap Δ . The Δ 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 Δ below T c is slow as compared with that of BCS gap probably reflecting the unconventional superconductivity in CeCoIn 5 .