Electromagnetic properties of Bi-2223/Ag concentric tapes

It is well established that near the silver interface highly textured Bi-2223 layers compared to the inner ceramic core may be obtained. Thus Bi-2223 multilayered concentric tapes with silver matrix are very promising in increasing transport critical current densities. In the present work we report on the electromagnetic characterization of short tapes having in their cross-section a very thin HTS flattened ring with Ag inside and outside of it. The samples were prepared by the powder in tube method and have self-field critical current densities J/sub c/ of the order of 3/spl times/10/sup 4/ A/cm/sup 2/ at 77 K. Transport and SQUID magnetization measurements revealed weak link nature of the samples in low magnetic fields. Large transport J/sub c/(B) hysteresis was observed at 4.2 K and magnetic fields up to 20 T. Magnetic field profiles measurements with miniature Hall sensors are in qualitative accordance with model calculations supposing homogeneous current density distribution across the superconducting core.