Fabrication of laminated Bi-2212/Ag multifilamentary tape

The powder-in-tube (PIT) process has been successfully used to make long lengths of Ag-sheathed oxide superconductors. A modified PIT approach is proposed to fabricate conductors with laminated Bi-2212 configurations. Ag/Bi-2212 tapes consisting of seven laminae were produced with various thicknesses ranging from 0.38 to 0.25 mm. The use of a turkshead was found to be beneficial, yielding tapes with good dimensional integrity and consistency. Critical current density (J(c)) values greater than 10(5) A cm(-2) (0.01 T and B perpendicular to tape surface) have been attained for tapes of different thicknesses. Nonetheless, J(c) was found to be related to the average thickness of individual Bi-2212 lamina. It is believed that excessive cold working accounts for the decrease in J(c) with decreasing size below a threshold value. The enhancement of J(c) is attributed to the high Bi-2212 grain alignment along the Ag-oxide interfaces and uniform dimensions within the laminate conductors.