Dynamic response of Ag-Bi2223 tapes in applied fields by electric transport measurement

Electric transport measurement of Ag-sheathed Bi2-xPbxSr2Ca2Cu3Oy tapes in magnetic fields H was conducted by the four-probe method to study the effec t of H and sweeping rate of applied current dt/dt on critical current. It i s found that H and dI/dt apparently affect the critical current and the V-I characteristic curve. To understand the experimental result, numerical sim ulation was carried out based on the collective creep model of the vortex g lass. The numerical result is in agreement qualitatively with the experimen t. It is shown that the influence of the applied field, temperature and vor tex pinning on the normalized critical current can be reduced to a single c ritical current parameter n. (C) 2000 Elsevier Science Ltd. All rights rese rved.