PREPARATION OF SINGLE HIGH-TC PHASE SAMPLES OF BI-PB-SR-CA-CU-O SUPERCONDUCTORS

Two series of samples with starting compositions of (Bi1-yPby)2Sr2Ca2 Cu3O10 + x, y = 0.05, 0.10, 0.15 and 0.20, and (Bi0.9Pb0.1(1 + z))2 Sr2Ca2 Cu3O10 + x, z = 0, 0.30 and 0.50 were prepared by a solid state reaction under low oxygen pressure. This was done to reveal the amount of Pb substituent needed for the formation of a single high Tc phase, which was detected by X-ray diffraction. It was shown that the formation of the single high Tc phase is possible provided that there is a slight excess of Pb in the starting composition. The single high Tc phase samples prepared in this way exhibited a Tc(R = 0) of 108 K and Jc, at 77 K and zero applied field, of up to 1070 A cm-2. © 1990.