TRANSPORT CURRENTS AND MAGNETIC-PROPERTIES OF TEXTURED BI(2223) TAPE

Magnetic and transport properties of textured Bi(2223) tape with high critical transport current density (j(c)(77 K, 0 T) = 2.8 x 10(4) A cm-2)were studied. Magnetic measurements show non-granular behaviour of shielding and transport currents for the magnetic field orientation perpendicular to the tape plane B perpendicular-to p at low temperatures and low fields. At high magnetic fields and temperatures, however, qui e large differences were observed, which depend on magnetic field sweep rate B and voltage criteria E(c). This is connected with granularity and inhomogeneity of the current flow. It was established that the magnetic field dependence of the critical current has a general scaling behaviour:j(c)(B, B, T) = j(c)(0, B, T)f(B/B(o)(B, T)) where the scaling function f becomes exp(-B/B(o)) for B/B(o) greater-than-or-equal-to 1. The scaling parameter B(o) is proportional to the irreversibility field B(irr). Both B(o) and B(irr) show an exponential temperature dependence.