Magnetic Flux-Trapping of Anisotropic-Grown Y-Ba-Cu-O Bulk Superconductors during and after Pulsed-Field Magnetizing Processes
Magnetic Flux-Trapping of Anisotropic-Grown Y-Ba-Cu-O Bulk Superconductors during and after Pulsed-Field Magnetizing Processes
复制标题
脉冲场磁化过程中和之后各向异性生长的 Y-Ba-Cu-O 体超导体的磁通量捕获
DOI：
10.1088/1742-6596/507/1/012039
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
M. Langer
中科院分区：
文献类型：
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作者：
T. Oka;Y. Yamada;T. Horiuchi;J. Ogawa;S. Fukui;T. Sato;K. Yokoyama;M. Langer
对熔融织构Y-Ba-Cu-O高温超导块材磁体在30 K下脉冲磁场磁化过程中及磁化后的磁通渗透进行了精确的测量。采用冷籽晶法制备了由Nd-Ba-Cu-O薄膜组成的单晶和双晶磁体。将这些晶种置于前体的顶表面上以使大晶粒在热处理期间生长。我们观察到，在3.1 T附近，双籽晶样品的磁通穿透发生在较低的外加场区域，而单籽晶样品的磁通穿透发生在3.8 T附近。这意味着磁通量能够比单种子更容易地侵入双种子样品。结果表明，平行和垂直于籽晶排的各向异性晶粒生长影响了钉扎中心分布不同时Jc值的变化，从而导致了磁场的优先侵入路径。
The magnetic flux penetration into the melt-textured Y-Ba-Cu-O high temperature superconducting bulk magnets were precisely evaluated during and after the pulsed field magnetization processes operated at 30 K. The bulk magnets were carefully fabricated by the cold seeding method with use of a single and a pair of seed crystals composed of the Nd-Ba-Cu-O thin films. These seed crystals were put on the top surfaces of the precursors to let the large grains grow during the heat treatments. We observed the flux penetrations which occurred in the lower applied-field regions at around 3.1 T for the samples bearing the twin seeds than those of the single-seeded crystals at around 3.8 T. This means that the magnetic fluxes are capable of invading into the twin-seeded samples more easily than the single-seeds. It suggests that the anisotropic grain growths of parallel and normal to the rows of seed crystals affects the variations of Jc values with different distributions of the pinning centers, results in the preferential paths for the invading magnetic fluxes.