UNUSUAL RESISTIVE TRANSITIONS IN 2-PHASE SUPERCONDUCTING SINGLE-CRYSTALS - BISRCACUO WHISKERS

Silver pressure contacts were attached to very small two-phase whisker s of BiSrCaCuO and four-probe c-axis resistive transitions were measur ed. On cooling down, the high-T-c phase shows up as an increase in res istance followed by the usual drop to zero resistance of the dominant low-T-c phase. A model calculation, which scales the highly anisotropi c whisker into an isotropic normal material with a superconducting she et inclusion at various locations, reproduces the essential results. ( C) 1997 Elsevier Science B.V.