Enhancement in flux pinning and irreversibility field by means of a short-time annealing technique for ? superconductor
Abstract
We have successfully prepared mercury-based high-temperature superconductors of composition 0953-2048/10/11/008/img8 by means of the encapsulation and short-time annealing technique. By measuring the hysteresis loops, the critical current density 0953-2048/10/11/008/img9 is determined by using Bean's model. Scaling behaviours of the pinning-force density are discussed. By using the short-time annealing technique, the irreversibility line and the flux-pinning properties of the Hg-1223 specimen were enhanced by the introduction of more lattice defects, such as screw dislocations, intergrowth structures and stacking faults, into the Hg-1223 specimen. Furthermore, it is shown that the temperature dependence of the irreversibility line 0953-2048/10/11/008/img10 exhibits different features within two temperature regions. In the low-temperature region 0953-2048/10/11/008/img10 is proportional to 0953-2048/10/11/008/img12, while in the high-temperature region 0953-2048/10/11/008/img10 is proportional to 0953-2048/10/11/008/img14. The observed 0953-2048/10/11/008/img10 can be clarified by comparison with the theoretical model.
- Publication:
-
Superconductor Science Technology
- Pub Date:
- November 1997
- DOI:
- 10.1088/0953-2048/10/11/008
- Bibcode:
- 1997SuScT..10..836H