Enhanced pinning by second-phase precipitates in Sr rich “Bi 2Sr 2CaCu 2O 8” ceramics

Abstract

From a consideration of the phase equilibrium diagram of the system Bi 2O 3SrOCaOCuO, a simple annealing procedure was developed to precipitate Bi 2+ x Sr 2− x CuO 6+ d , Sr 14Cu 24O 41− x and Bi 2Sr 3O 6 in high-temperature superconducting “Bi 2Sr 2CaCu 2O 8” ceramics. The transformation results in a four-fold increase of the critical current density at 0.5 to 1 T, which is believed to reflect the increased pinning properties of these ceramics by second-phase precipitates.