ENGINEERED FLUX PINNING CENTRES IN PB-DOPED HIGH TEMPERATURE SUPERCONDUCTING BI2SR2CACU2O8 CERAMICS

摘要

The Pb solubility of ''Bi2Sr2CaCu2O8'' is determined within the concentration range Bi2.18-xPbxSr2CaCu2O8+d with 0 less than or equal to x less than or equal to 0.6 and the temperature range from 800 to 900 degrees C. From a consideration of the Pb solubility in ''Bi2Sr2CaCu2O8'' a simple annealing procedure was developed to precipitate (Pb, Bi)(4)(Sr, Ca)(5)CuO10+d (451 phase) in high-temperature superconducting Ph-rich ''Bi2Sr2CaCu2O8'' ceramics. The precipitation results in a two-fold increase of the critical current density which is believed to express improved pinning properties of the superconducting ceramics. The microstructures of the samples with increased critical current density were studied with respect to the grain size and volume content of the 451 phase. [References: 34]