Relaxation properties of the trapped flux of bulk high-temperature superconductors at different magnetization levels
Relaxation properties of the trapped flux of bulk high-temperature superconductors at different magnetization levels
复制标题
不同磁化水平下大块高温超导体的俘获通量的弛豫特性
DOI：
10.1007/s10948-011-1312-4
复制
发表时间：
2012
影响因子：
1.8
通讯作者：
M.Izumi
中科院分区：
文献类型：
--
作者：
Z.Deng;K.Tsuzuki;M.Miki;B.Felder;S.Hara;M.Izumi
磁弛豫现象是块体高温超导体（HTS）工程应用中的一个关键问题，在高温超导体中，由于材料内部的固有磁流变，捕获场或悬浮力表现为随时间的衰减。为了充分利用体高温超导的高俘获场，我们实验研究了体高温超导在不同磁化水平下的俘获通量弛豫特性。在不同的激发场条件下，分析比较了场冷却磁化和零场冷却磁化条件下捕获场与弛豫速率的关系。同时，在单一磁化过程中，可以同时测量不同捕获磁通的弛豫率。弛豫率与捕获场密切相关，有助于反映后续再磁化过程的效果。为了抑制弛豫，我们进一步从材料改进、工作温度和熔剂退火效果三个方面考察了可能的方法。
The magnetic relaxation phenomenon is a crucial subject for the engineering applications of bulk high-temperature superconductors (HTS) in which the trapped field or levitation force behaves with a time-dependent decay due to the intrinsic flux creep inside the HTS materials. To fully exploit the high trapped field of bulk HTS, we have experimentally investigated the trapped flux relaxation properties, especially at different magnetization levels. With different excitation fields, the dependence between trapped field and relaxation rate was analyzed and compared in both field-cooling magnetization (FCM) and zero-field-cooling magnetization (ZFCM) conditions. In parallel, the relaxation rates for different trapped flux can be measured all at once during a single magnetization process. The relaxation rate is closely correlated to the trapped field and useful to reflect the effect of the following remagnetization processes. To suppress the relaxation, we further checked possible methods from the three aspects of material improvement, working temperature and flux annealing effect.