A trapped field of >3 T in bulk MgB2 fabricated by uniaxial hot pressing
A trapped field of >3 T in bulk MgB2 fabricated by uniaxial hot pressing
复制标题
单轴热压制备块状 MgB2 中 >3 T 的俘获场
DOI：
10.1088/0953-2048/25/11/112002
复制
发表时间：
2012
影响因子：
3.6
通讯作者：
D. Cardwell
中科院分区：
文献类型：
--
作者：
J. Durrell;C. Dancer;A. Dennis;Yan Shi;Z. Xu;A. Campbell;N. H. Babu;N. H. Babu;Richard I. Todd;Chris R. M. Grovenor;D. Cardwell
在直径为25mm，厚度为5.4 mm的两个盘状MgB2超导体的磁化堆中，在17.5 K下测量到一个超过3t的捕获场。体积MgB2样品是通过单轴热压制备的，这是一种易于扩展的工业技术，达到其最大理论密度的91%。利用Biot-Savart定律从捕获场数据推导出的宏观临界电流密度与实测的局部临界电流密度一致。由此我们得出结论，临界电流密度以及因此产生的捕获场性能受到MgB2中可用的磁通钉接的限制，而不是由于缺乏连通性。这有力地表明，增加样品尺寸和通过掺杂增强钉住将允许进一步提高块状MgB2的捕获场性能。
A trapped field of over 3 T has been measured at 17.5 K in a magnetized stack of two disc-shaped bulk MgB2 superconductors of diameter 25 mm and thickness 5.4 mm. The bulk MgB2 samples were fabricated by uniaxial hot pressing, which is a readily scalable, industrial technique, to 91% of their maximum theoretical density. The macroscopic critical current density derived from the trapped field data using the Biot–Savart law is consistent with the measured local critical current density. From this we conclude that critical current density, and therefore trapped field performance, is limited by the flux pinning available in MgB2, rather than by lack of connectivity. This suggests strongly that both increasing sample size and enhancing pinning through doping will allow further increases in trapped field performance of bulk MgB2.