抄録
Melt-textured YBa2Cu3Ox superconductors made by the QMG process were applied as current lead. The current lead consisted of the QMG-YBa2Cu3Ox, pure silver flexible current lead sheets, a protective stainless pipe and copper electrodes. The YBa2Cu3Ox was cooled by thermal conduction through the silver sheets. These current leads were used for a critical current measuring holder to demonstrate the performance of these materials in a magnetic field. The consumption rate of liquid helium was extremely reduced to about 25% in comparison with that of a conventional holder using seven φ2mm Cu current leads, which is available for measuring six samples for a transport current up to 200A. These current leads were operated in a stray field of 0.4T at 50K when the hybrid magnet generated 23T. It was found that QMG bulk superconductor is surely as effective as current leads used in high magnetic fields at high temperature. The advantage of QMG current leads lies in high performance in the magnetic field. In addition, compact cryogenic equipment can be realized by adopting YBa2Cu3Ox superconductors without a weak-link.
