ABSENCE OF A TAFF-REGION IN BI-2223 COMPOSITE TAPES

For Ag sheathed textured (Bi1-xPbx)2Sr2Ca2Cu3O10 tapes the electric fi eld as a function of current density, temperature and magnetic field h as been investigated in the thermal activation region in fields up to 4 T. From the results the temperature and field dependence of critical current density is derived. In low magnetic field no current independ ent region of the resistivity is found up to the lowest current values , indicating that no TAFF region exists. The results are discussed wit hin the current models for thermal activation.