Magnetic shielding and trapping properties of BPSCCO superconducting tubes

Tubular superconducting magnetic shields were prepared from the (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10+x/ superconductor. A single tube of wall thickness of only 1.8 mm traps magnetic flux density of 30 mT at the temperature T=77.3 K and 60 mT at 63.2 K, while for a coaxial system of five tubes of overall thickness 9.6 mm, it increases to 70 mT at 77.3 K. A shielding factor as high as 5/spl times/10/sup 6/ was found for the superconducting tube of inner diameter d=22 mm and length and inner diameter ratio l/d=4.6.<>