Pulse field magnetization for disc-shaped MgB2 Bulk Magnets
Pulse field magnetization for disc-shaped MgB2 Bulk Magnets
复制标题
圆盘状 MgB2 块状磁体的脉冲场磁化
DOI：
10.1109/tasc.2016.2639298
复制
发表时间：
2016
影响因子：
1.8
通讯作者：
W. Haessler
中科院分区：
文献类型：
--
作者：
Taisuke Miyazaki;Jun Ogawa;Satoshi Fukui;Takao Sato;Tetsuo Oka;Kazuya Yokoyama;Kulawansha Eranda;Yuanding Zhao;J. Scheiter;W. Haessler
MgB2块体磁体是一种颇具吸引力的块体超导体，因为它们具有均匀的俘获场分布、材料成本低、重量轻等优点。脉冲场磁化 (PFM) 在结构紧凑、磁化时间较短以及磁化大块样品的廉价方法方面也具有一些有效的优势。然而，由于磁通量运动的突然变化而产生热量，PFM 的俘获场不如场冷却磁化的俘获场。特别是MgB2块状磁体由于其比热低，温升显着。在这项研究中，我们对五层或三层MgB2块状样品进行了PFM技术来分析通量侵入行为。这些样品是通过球磨和热压制造的。结果，当施加 0.90 T 的外部磁场 Bex 时，在最顶部样品中心的 14.6 K 处获得了 BT= 0.64 T 的最大俘获场。随着Bex进一步增加，BT因发热而急剧下降。此外，在高于 2.0 T 的应用场中经常发生磁通量跳跃。
MgB2bulk magnets are one of the attractive bulk superconductors because they have homogeneous trapped field distribution, low material costs, lightweight, and so on. Pulse-field magnetization (PFM) also has some effective advantages in the point of view of compact setup, shorter magnetizing time, and an inexpensive way to magnetize the bulk samples. However, the trapped field by PFM is inferior to those by field cooling magnetization due to the heat generation caused by sudden changes of the magnetic flux motion. Especially, the temperature rise is remarkable for MgB2bulk magnets because of its low specific heat. In this study, we have carried out the PFM technique for five-stacked or three-stacked MgB2bulk samples to analyze the flux-invasion behavior. These samples were fabricated by ball-milling and hot-pressing. As a result, maximum trapped field ofBT= 0.64 T was obtained at 14.6 K at the center of the topmost sample when the external magnetic fieldBexof 0.90 T was applied. AsBexincreases further,BTwere dramatically decreased because of heat generation. Furthermore, flux jumps frequently took place in the applied field higher than 2.0 T.