THE LOCAL PHASE CONVERSION AND CRITICAL-CURRENT DENSITY OF SILVER-DOPED(BI PB)(2)SR2CA2CU3OX TAPES/

The effect of silver doping on the local phase conversion and critical current density of silver-sheathed (Bi/Pb)2223 tapes has been studied . Four tapes were prepared using precursor powers produced by the Evap orative Decomposition of Solution (EDS) method. The control tape had a nominal stoichiometry of Bi1.84Pb0.34Sr1.91Ca2.03Cu3.08Ox7 whilst the second and third tapes had 8 wt% and 15 wt% silver, respectively, add ed during the EDS process. Using this method the silver can be homogen eously mixed with the oxide material on an atomic scale. For the fourt h tape, 8 wt% silver particles were mixed by hand with the EDS process ed powder. We have found that the silver additions tend to enhance and homogenize the local phase conversion throughout the core of the tape s, although no significant difference has been observed in the critica l current densities for the different samples, The maximum J(c) (77 K, self-field) obtained in these tapes is about 1.8 x 10(4) A cm(-2). (C ) 1997 Published by Elsevier Science Ltd.