Relation between Critical Current Densities and Normal-State Resistivities in (BI, Pb)-Sr-Ca-Cu-O Superconducting Tapes

摘要

The critical current density, Jc, under self magnetic field and the temperature dependence of the normal-state resistivity rho(T) in short moncore Bi_(1.8)Pb_(0.4)Sr_2Ca_(2.2)Cu_3O_x tapes with and without silver sheath were measured by the four terminal method. The samples were babicated by the conventional powder-in-tube method under various sintering temperatures (816 deg C approx 846 deg C). The silver sheath of the tape was peeled off after sintering. It is assumed that rho(T) contains an intragrain resistivity rho_8 contains an intragrain resistivity rho_8, integrain resistivity rho_c and effective area factor alpha which is related to percolative current path by a phenomenological model. The value of J_c at 77K is inversely proportional to rho_c and approximately proportional to the parameter alpha logarithmically.