IMPROVEMENT IN PARAMETER SPREADS OF YBACUO PRBACUO/YBACUO TRILAYER JUNCTIONS/

An improvement in the distribution of junction properties for YBaCuO/P rBaCuO/YBaCuO trilayer junctions has been demonstrated. In order to en sure a uniform substrate temperature during the deposition of trilayer films, Al/Cu/Al stacked foils are introduced as a backing plate betwe en the substrate and sample holder. Furthermore, the film composition is optimized to reduce the precipitated particles on the surface of th e films. All the junctions with a barrier thickness of 35 nn and an ar ea less than 100 mu m(2) show RSJ-like current voltage characteristics with some excess current at 4.2 K. The 1-sigma spreads of Josephson c ritical current density J(c) and normalized junction resistance R(n)A are obtained to be 34% and 25%, respectively, for 88 junctions on the same substrate. This result is comparable to the 1-sigma spreads of ra mp-edge type junctions.