Superconductivity in Bi 2223 compound: physics and potential applications

The main results of the systematic study of the electron transport properties and AC susceptibility in Pb-doped, almost single phase, Bi 2223 ceramic samples and Ag-clad Bi 2223 tape, are presented. Whereas the results for the ceramic samples can only be used for the study of the percolation problem in the weak-link network, those for tape can yield some intrinsic parameters of Bi 2223 compound (the upper critical fields B_C2, the coherence lengths, etc.). In addition, the results for the tape provide some technologically relevant parameters (the pinning potential U_0, volume pinning force F_p and the flux-flow viscosity h) and an insight into the nature of dissipation and pinning in these materials. Some factors limiting the critical current density J_c in the present-day tapes are briefly discussed

Supravodljivost u spoju Bi 2223: fizika i moguće primjene

The main results of the systematic study of the electron transport properties and AC susceptibility in Pb-doped, almost single phase, Bi 2223 ceramic samples and Ag-clad Bi 2223 tape, are presented. Whereas the results for the ceramic samples can only be used for the study of the percolation problem in the weak-link network, those for tape can yield some intrinsic parameters of Bi 2223 compound (the upper critical fields BC2, the coherence lengths, etc.). In addition, the results for the tape provide some technologically relevant parameters (the pinning potential U0, volume pinning force Fp and the flux-flow viscosity h) and an insight into the nature of dissipation and pinning in these materials. Some factors limiting the critical current density Jc in the present-day tapes are briefly discussed.Prikazani su glavni rezultati sustavnog istraživanja električnih svojstava i inicijalne susceptibilnosti gotovo–monofaznih Bi 2223 keramičkih uzoraka dopiranih olovom i srebrom obložene vrpce. Dok se rezultati za keramičke uzorke mogu primjenjivati isključivo za proučavanje perkolacije u sustavu slabih veza, oni za traku daju neke intrinsične parametre Bi 2223 spoja (viša kritična polja i duljine koherencije). Nadalje, rezultati za traku daju neke tehnološki važne parametre (potencijal zapinjanja U0, volumnu gustoću sile zapinjanja Fp i viskoznost tečenja magnetskih vrtloga η) i uvid u prirodu rasipanja energije i zapinjanja vrtloga u tim materijalima. Ukratko su razmotreni razlozi ograničenja kritičnih struja u vrpcama