Electric Properties of the Y-Ba-Cu-O/Ag Interface

Abstract

The energy gap parameter 2 Δ induced in Ag, evaporated on an Y-Ba-Cu-O (YBCO) film, was determined by a quasi-particle tunneling experiment for a YBCO/Ag/PbO _x /Pb junction. The energy gap 2 Δ was as large as 35 mV at 4 K and decreased almost linearly with an increase in temperature, vanishing at about 45 K. The same type of junction with a larger tunnel conductance showed a tunnel-type Josephson characteristic below the critical temperature of Pb.