Optimization of (Bi, Pb)2Sr2Ca2Cu3O10/Ag conductors for practical applications

In this paper we report some of the most recent developments of silversheathed (Bi,Pb)2Sr2Ca2Cu3O10 (Bi-2223) tapes that are currently under analysis in view of the potential future applications of these conductors. Various attempts for improving the tape behaviour in the presence of high magnetic fields and/or ac's are actively carried out. A substantial improvement in the magnetic field dependence of the critical current density was observed in Bi2223/Ag tapes that were cooled at very slow rates after the final heat treatment process. This result was attributed to the reduction in the Pb content inside the Bi2223 phase. A clear reduction in the ac losses was observed by ac susceptibility measurements performed on twisted Bi-2223 tapes including an insulating barrier capable of enhancing the transverse resistivity of the silver matrix.