Temperature dependence of filament-coupling in Bi-2223 tapes: magnets-optical study
Temperature dependence of filament-coupling in Bi-2223 tapes: magnets-optical study
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DOI：
10.1088/0953-2048/13/2/312
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发表时间：
2000-02-01
影响因子：
3.6
通讯作者：
Gaevski, ME
中科院分区：
文献类型：
--
作者：
Bobyl, AV;Shantsev, DV;Gaevski, ME
本文用磁光成象方法研究了在20 K至Tc温度范围内，Ag包套的Bi_2Sr_2Ca_2Cu_3O_（10+）δ超导带材中，超导细丝间通过无规超导桥的耦合。本文测量了在强垂直磁场作用下，处于静止状态的完整磁带表面的磁通量分布。在低温下观察到的通量分布反映了单个细丝的排列。在高温下，分布变得更类似于均匀的单芯带，表明超导连接出现在灯丝之间。为了讨论丝内电流和丝间电流的相对贡献，提出了一个基于Bean临界状态的简单模型，并应用于分析温度依赖性行为。丝间耦合，随着温度的增加，在77 K时达到一个点，其中在大的丝间回路中流动的电流大致等于丝内电流。
Coupling through random superconducting bridges between filaments in a multifilamentary Ag-sheathed Bi2Sr2Ca2Cu3O10+delta tape has been investigated by magneto-optical imaging at temperatures from 20 K up to T-c. Magnetic flux distributions have been measured on the surface of an intact tape in the remanent state on applying a strong perpendicular magnetic field. The flux distributions observed at low temperatures reflect the arrangement of individual filaments. At high temperatures, the distribution becomes more similar to that for a uniform monocore tape, indicating that superconducting connections appear between the filaments. To discuss the relative contributions of the intra- and inter-filament currents, a simple model based on the Bean critical state was proposed and applied to analyse the temperature dependent behaviour. The inter-filament coupling, increasing with temperature, reaches at 77 K a point where the currents flowing in large inter-filament loops are roughly equal to the intra-filament currents.