Electrical Transport Properties of (Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10))/Ag Tapes with Different Nanosized MgO

摘要

MgO nanopowders with average size 20 and 40nm were introduced into (Bi_(1.6)Pb_(0.4)Sr_2Ca_2Cu_3O_(10))(MgO)_x (x = 0–0.15 wt.%) in the pellet form. The optimum amounts for the highest transport critical current density J_c were x = 0.10 and 0.01 wt.% for 20 and 40nm MgO, respectively.These results were used to fabricate MgO added (Bi, Pb)-2223/Ag sheathed tapes using the powder-intubemethod. The tapeswere sintered at 845℃ for 50 h and 100 h.The structure, microstructure, and J_c of the tapeswere determined. The temperature and magnetic field dependence of J_c for the MgO added tapes exhibited a significant enhancement compared with the nonadded tapes. J_c of 20nm MgO added tape was higher compared with the 40nm MgO added tape. A higher J_c was obtained when the tapes were sintered for 100 h. The increase in J_c can be explained as the increase of the flux pinning strength by nanosized MgO. The nanoparticle with size closer to the coherence length was more effective in enhancing J_c.