H. Nadifi et al., Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO3, SUPERCOND S, 13(8), 2000, pp. 1174-1179
Preparation of Bi-2223/Bi-2310 and Bi-2212/BiFeO3 composites has been perfo
rmed so as to obtain some active composites where the superconductive prope
rties of Bi-2223 or Bi-2212 can be modified using a property of the insulat
ing phase. In both eases superconductive percolation was obtained, but only
in the case of a Bi-2223 (or Bi-2712)/Bi-2310 composite was no (or very we
ak) chemical reaction observed during sintering. Since the superconductive
percolation threshold was obtained in this case for a concentration of Bi-2
223 or Bi-2212 lower than 20%, a special composite model had to be consider
ed. The Bi-2212/BiFeO3 system is very interesting due to the ferroic proper
ties of BiFeO3. Superconductive percolation was achieved with this mixture
too, but with more difficulties because of a chemical reaction occurring be
tween the two compounds during sintering. A study of the properties of thes
e composites has been performed and will be briefly described in what follo
ws. The good quality of the Bi-2223(or Bi-2212)/B1-2310 composite enables u
s to expect same future applications.