Distribution of superconducting energy gaps in GdBa2Cu3O7 obtained from point-contact spectroscopy

Point-contact spectra of GdBa 2 Cu 3 O 7 (with Ag as counterelectrode) exhibit reproducible wide minima in the differential resistance dV/dI vs voltage V, which are attributed to the superconducting energy gap. The energy positions and widths of these gap features correspond to the gap distribution extracted earlier from YBa 2 Cu 3 O 7 point-contact spectra (with narrow gap minima). A comparison with the Blonder-Tinkham-Klapwijk model suggests that the distribution of wide gaps in GdBa 2 Cu 3 O 7 results from orificelike point contacts