POINT-CONTACT TUNNELING INVESTIGATION OF THE SUPERCONDUCTORS IN Y-Ba-Cu-O SYSTEM

Point-contact tunneling measurements of the oxide superconductor Y-Ba-Cu-O were carried out with both Nb and Mo tips. An energy gap, Δ=18.5meV and 2Δ/kT_c=4.7 were obtained. The result is consistent with the strong-coupling theory. The tunneling conductance curves indicate a granular feature of the sample.