Ag/Bi 2212 tapes prepared by alternating electrolytic deposition and heat treatments

Ag/Bi 2212 tapes have been prepared by oxidation of 3.5 mu m thick precusors deposited electrolytically in a sequential way on both sides of a 50 mu m thick silver backing. As in the standard procedure known as "partial melting growth" our layers are partially melted, but because they are very thin they cannot be maintained in the melted state for more than a few minutes without de-wetting. Hence instead of cooling them slowly we quench them to room temperature after a short stay in the melted state and finally treat them just under the melting point of the Bi 2212. To optimize the process the microstructure of our samples was characterized at-each stage of their preparation. Here down we start with a comparison between the standard procedure and our modified one. Next we present a correlation between the process and the microstructure from the one hand, and the microstructure and the electrical and magnetic properties from the other hand. At the present level of optimization, we produce on a regular basis samples which exhibit a critical current density of 30 000 A/cm(2) at 77 K and 300 000 A/cm(2) at 4.2 K. These values correspond to transport currents of respectively 6.3 and 63 A for specimens of 3 mm in width, with a substrate 7 times thicker than the 2 superconducting layers. Moreover, we have checked that the transport critical current is proportional to the width of the specimen, leading to 42 A at 77 K and 100 A at 63 K for specimens of 20 mm in width.