Crystallographic, thermodynamic and transport properties of Bi sub 2 Sr sub (3-x) Ca sub x Cu sub 2 O sub (8-delta) superconductor.

We have demonstrated the presence of a single phase solid solution for the Bi sub 2 Sr sub (3-x) Ca sub x Cu sub 2 O sub (8+delta) superconductor, in the 1.25 = x = 2.0 range. The lattice parameters and melting points vary monotonically with x, both increasing towards the Sr-rich composition. This monotonic variation of the lattice parameters extends into the 0.8 = x = 2.2 range, however the material is multi phased outside the 1.25 = x = 2.0 limit. Superconducting onsets in the ranges of 70-89 and 108-118K have been obtained; however the exact results are very sensitive to processing parameters. Magnetization measurements indicate high intragranular current densities (J sub c) at 5K of ~5 x 10 sup 6 A/cm sup 2. The actual transport J sub c is low (~ 70A/cm sup 2 at 4K) and exhibits a severe field dependence similar to the behavior of YBa sub 2 Cu sub 3 O sub 7 superconductor.