The increase of pinning in (Bi,Pb)₂Sr₂Ca₂Cu₃O_10+dbulk ceramics

Abstract

Considering the phase equilibrium diagram of the Bi2O3-PbO-SrO-CaO-CuO system, ceramics of the 2223 phase with the composition Bi1.8Pb0.4Sr2Ca2Cu3O10+d have been transformed by a simple annealing procedure into multi-phase samples. The transformation results in a four-fold increase of the critical current density at 2 T and 30 K (three-fold at 1 T and 50 K), which is believed to express an enhanced pinning capacity of the material. The nature of the pinning centres produced is not yet clarified.