The critical current density and microstructure of Ag sheathed Bi(2223) superconductors

The densification effect of the oxide core was investigated for a Ag sheathed (Bi, Pb) 2 Sr 2 Ca 2 Cu 3 O x tape to improve its weak link property and thus increase the critical current density, J c . The density of the oxide core estimated from the Vickers hardness increased after the improvement of the cold working condition. This densification caused fewer voids between the crystals and the smaller second phase after heat treatment. As a result, J c value at 77K reached 66000 A/cm 2 at 0 T and 14500 A/cm 2 at 1 T.