IMPROVEMENT OF THE MAGNETIC SHIELDING AND TRAPPING PROPERTIES OF BIPBSRCACUO SUPERCONDUCTING TUBES BY THE USE OF MULTIPLE THERMOMECHANICAL PROCESSING

A series of (Bi0.9Pb0.1)2Sr2Ca2Cu3O10+x superconducting tubular shields was prepared by repeated thermomechanical processing, cold isostatic pressing combined with a thermal treatment. The applied procedure provided the desirably textured material and enhanced the apparent pinning potential U0*. Thus the shielded (B(sh)) and trapped (B(tr)) magnetic-flux densities of more than 20 mT at the temperature of 77.3 K could be routinely reached in superconducting tubes with a wall thickness of about 2 mm. Based on the measurement of the time decay of B(tr) in a medium region of the magnetic field B, the U0* is similar to B-0.59 dependence, close to the expected U0* is similar to B-0.5 one, confirming the two-dimensional character of the BiPbSrCaCuO superconductor, was experimentally found.