PREPARATION AND SUPERCONDUCTIVITY OF SINGLE PHASE Bi1.65Pb0.35Sr2Ca2Cu3Oy WITH ZERO RESISTANCE TEMPERATURE 106.5K

Samples with nominal composition Bi2-xPbxSr2Ca2Cu3Oy(x = 0.30;0.35;0.40;0.45) have been prepared by solid state reaction. Phase and structure analyses have been performed, and the resistance-temperature relation and dc susceptibility have also been measured. The results show that the sample with x = 0.35 is a single-phase material. X-ray analysis and electron differaction indicate that its phase structure is similar to that of 2223 phase, it is tetragonal with a = b = 5.414?, c = 37.106?, we observed also the modulated structure along a and b. The results of resistance-temperature and dc susceptibility measurement show that, when T = 50 K, there is only one superconducting phase of 107K. In addition, we find that the preparation condition of the single-phase material (composition, sintering temperature and the quenching rate) is stringent. Like the 1-2-3 phase material, the oxygen content not only influences the phase, zero-resistance temperature of the sample, but also influences the transport property of normal state.