Effect of grain network modifications due to additives on critical current ( Ic) in Bi-2212 superconductor
Abstract
The presence of weak links in high- Tc superconductors is a major drawback in achieving high critical current densities. The present study deals with the effect of additives (Ag, Ag 2O and BaBiO 3) on the weak link behaviour of Bi-2212 in bulk form. It is observed that the addition of silver (Ag) metal powder improves the connectivity between the grains by proximity-effect and thereby enhances the current carrying capability at temperatures very close to Tc. De Gennes and Clarke models have been invoked to establish that Bi-2212 containing insulating additives (BaBiO 3 and Ag 2O) show a superconductor-insulator-superconductor (S-I-S) type grain network and thereby enhance the weak link behaviour, whereas metallic Ag addition shows a superconductor-normal metal-superconductor (S-N-S) behaviour and is, therefore, a potential candidate for large scale applications. Further support to this data is obtained from ac susceptibility studies carried out at different magnetic field strengths (0.1-4.0 Oe).
- Publication:
-
Physica C Superconductivity
- Pub Date:
- May 1999
- DOI:
- 10.1016/S0921-4534(99)00249-X
- Bibcode:
- 1999PhyC..316..119R