We have studied the effect of preloading on the relaxation of the levitation force of bulk Y-Ba-Cu-O superconductors. The levitation force was measured by applying the external field with a superconducting solenoid. We set the standard magnetic induction (Bst) to be 1.2 T supposing that the bulk Y-Ba-Cu-O disk experiences this field in operation. Preloading was applied such that the external field was first ramped to 1.1Bst and reduced to Bst. We confirmed that the preloading was effective in reducing the relaxation of the levitation force, although the effective levitation force was largely depressed compared to that without preloading. The employment of an extra step to lower the field below Bst before reaching B st was effective in improving the effective levitation force without sacrificing the ability to reduce the relaxation rate. This is qualitatively understood in terms of the field distribution inside the disk based on the critical state model.
|ジャーナル||Physica C: Superconductivity and its applications|
|出版ステータス||Published - 2005 10 1|
|イベント||Proceedings of the 17th International Symposium on Superconductivity (ISS 2004) Advances in Supeconductivity - |
継続期間: 2004 11 23 → 2004 11 25
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