a Faculty of Science, University of Hyogo, Ako-gun, Hyogo 678-1297, Japan b Department of Physics, Kyoto University, Kyoto 606-8502, Japan c Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan
Abstract:
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 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 Tc is slow as compared with that of BCS gap probably reflecting the unconventional superconductivity in CeCoIn5.
