Studies on the non rare earth oxide superconductors fabricated by sintering

Wire, tape, and bulk specimens of Bi-(Pb)-Sr-Ca-Cu-O material have been prepared. Studies on the superconducting properties and metallurgical studies have been conducted. The results of thermogravimetric analysis indicate that the phase transformation which accompanies absorption of oxygen does not occur in this material from 860°C down to 400°C. Tape specimens prepared by a combination of cold work and sintering showed J_c of 1100 A/cm² at 77 K with a good reproducibility. In these tape specimens, the c-axis of the grains tends to align perpendicularly to the tape surface. A 1330-filament Bi-Pb-Sr-Ca-Cu-O wire with a Ag matrix has been fabricated, showing high-T_c transitions when sintered at relatively low temperature. The concentration of Pb in the oxide must be controlled (reduced) before packing into an Ag sheath for the superconducting phase to be formed in a long wire. The results of this study indicate that the Bi-Sr-Ca-Cu-O system material has several favorable features which could make practical use of this material possible