Effect of MgO, Ag_2O, PtO_2 Particles on the Microstructure and Superconducting Properties of Ag Sheathed (Bi,Pb)-2223 Tapes

摘要

The effects of MgO, Ag_2O, PtO_2 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 J_c measurements. Samples were prepared with the composition Bi_(1.8)Pb_(0.4)Sr_(1.9)Ca_(2.1)Cu_(3.5)O_y to which 5wtprecent MgO, Ag_2O or PtO_2 particles with an average size of 0.5 #mu# m were added, respectively. The results indicate that the flux pinning is not clearly improved by the addition of MgO, Ag_2O or PtO_2 particles. However, MgO addition does not affect the formation rate of (Bi,Pb)-2223 phase, and can suppress the growth of secondary phases. Ag_2O or PtO_2 additions result in coarse secondary phases, and slow the formation rate of the 2223 phase.