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Critical currents and flux creep in melt processed high Tc oxide superconductors

✍ Scribed by M. Murakami; S. Gotoh; N. Koshizuka; S. Tanaka; T. Matsushita; S. Kambe; K. Kitazawa


Publisher
Elsevier Science
Year
1990
Tongue
English
Weight
684 KB
Volume
30
Category
Article
ISSN
0011-2275

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✦ Synopsis


YBa2Cu307 crystals fabricated by a quench and melt growth process contain fine Y2BaCuO5 particles. These fine precipitates are considered to have three beneficial effects: they suppress crack formation; they promote oxygen diffusion; and they act as pinning centres. Such crystals exhibit larger flux pinning than single crystals and their magnetic behaviour can be understood in terms of the critical state model which has been developed for conventional type II superconductors. Both transport and magnetization measurements gave Jo values exceeding 30 000 A cm-2 at 77 K and 1 T. Flux creep rate is also much smaller than that of single crystals and a value of pinning energy, U, comparable to that of conventional superconductors was obtained. A theoretical estimation of the contribution of 211 precipitates to flux pinning is also presented.


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