Effect of MgO, Ag2O, PtO2 Particles on the Microstructure and Superconducting Properties of Ag Sheathed (Bi,Pb)-2223 Tapes

The effects of MgO, Ag2O, PtO2 particles on the microstructure and pinning properties of Ag sheathed (Bi,Pb)-2223 tapes were studied by means of XRD, SEM, EDS, AC susceptibility and Jc measurements. Samples were prepared with the composition Bi1.8Pb0.4Sr1.9Ca2.1Cu3.5Oy to which 5wt% MgO, Ag2O or PtO2 particles with an average size of 0.5 µ m were added, respectively. The results indicate that the flux pinning is not clearly improved by the addition of MgO, Ag2O or PtO2 particles. However, MgO addition does not affect the formation rate of (Bi,Pb)-2223 phase, and can suppress the growth of secondary phases. Ag2O or PtO2 additions result in coarse secondary phases, and slow the formation rate of the 2223 phase.