Magnetic properties of Bi1.7Pb0.4Sr1.5Ca2.5Cu3.6Ox/(LiF)y superconducting system

AC complex susceptibility (with and without a superimposed DC field) and DC magnetization measurements on (Bi,Pb)-2223 high-temperature superconductors with various amounts of LiF are presented. The results are discussed in the frame of the critical state model. The values of the intra- and inter-granular critical current density as well as of fields for full penetration are estimated. It can be seen that, in Bi1.7Pb0.4Sr1.5Ca2.5Cu3.6Ox/(LiF)y, various amounts of LiF change the superconducting properties of both the grains and the inter-grain matrix. The intra-granular critical current density has similar values from both AC susceptibility and DC magnetization measurements, its highest value being attained for y=0.15. For all LiF-doped samples, a split of the peak corresponding to the dissipation in the grains was observed