Effect of nano-sized PbO on the transport critical current density of (Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10))/Ag tapes

摘要

The effect of nano-sized PbO (10-30 nm) addition on the transport critical current density, J_c of (Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10)) (PbO)_x (x=0-0.15 wt%) was investigated. J_c of PbO added pellet samples showed the maximal value at x=0.05wt%. Using this result, Ag-sheathed (Bi_(1.6)Pk_(0.4))Sr_2Ca_2Cu_3O_(10) (PbO)_xAg tapes (x=0 and 0.05 wt %) were fabricated by the powder-in-tube (PIT) method. The tapes were sintered for 50 h and 100 h at 845 °C. The temperature dependence of J_c for the non-added and PbO added tapes in applied field was investigated. J_c of the non-added tapes was 4510 A/cm~2 at 40 K and 949 A/cm~2 at 77 K. J_c of (Bi_(1.6)Pk_(0.4))Sr_2Ca_2Cu_3O_(10) (PbO)_(0.05)/Ag tape sintered for 100 h was 26,800 A/cm~2 at 40 K and 10,700 A/cm~2 at 40 K, which was higher than the tapes sintered for 50 h (8590 A/cm~2 at 40 K and 1880 A/cm~2 at 77 K). Nano-sized PbO added tapes sintered for 100 h showed a higher J_c (more than 10 times) under magnetic field (0-0.75 T) compared with the non-added tape. A combined effect of enhanced flux pinning and improved microstructure led to the significant increase in J_c of the nano-sized PbO added tapes.