Josephson Junctions Observed in La1.8Sr0.2CuO4 Superconducting Polycrystalline-Films

Abstract
La0.8Sr0.2CuO4 (LSC) superconducting polycrystalline films with onset T c of 32 K are fabricated using the sputtering method. By observing current voltage curves, the (100)-plane films are found to contain weak-link type Josephson-junctions in the film. The electrical resistivity and the maximum DC Josephson current in the films are also measured. Origins of the observed Josephson-junctions are discussed and compared with that of BaPb(1-x)Bi(x)O3. The LSC polycrystalline films are expected to be more useful than BPB films because of their higher T c.