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Development of the microstructure of uranium-doped Nd-Ba-Cu-O

Babu, NH and Kambara, M and Shi, Y and Cardwell, DA and Tarrant, CD and Schneider, KR (2003) Development of the microstructure of uranium-doped Nd-Ba-Cu-O. IEEE Transactions on Applied Superconductivity, 13. pp. 3147-3150. ISSN 1051-8223

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Melt grown Nd-Ba-Cu-O (NdBCO) has been reported to exhibit higher values of critical current density, J c and irreversibility field, H ir r, than other (RE)BCO superconductors, such as YBCO. The microstructure of NdBCO typically contains 5-10 μm sized inclusions of the Nd 4 Ba 2 Cu 2 O 10 phase (Nd-422) in a superconducting NdBa 2 Cu 3 O 7-δ phase (Nd-123) matrix. The average size of these inclusions is characteristically larger than that of the Y 2 BaCuO 5 (Y-211) inclusions in YBCO. As a result, there is scope to further refine the Nd-422 size to enhance Jc in NdBCO. Large grain samples of NdBCO superconductor doped with various amounts of depleted UO 2 and containing excess Nd-422 have been fabricated by top seeded melt growth under reduced oxygen partial pressure. The effect of the addition of depleted UO 2 on the NdBCO microstructure has been studied systematically in samples with and without added CeO 2 . It is observed that the addition of UO 2 refines the NdBCO microstructure via the formation of uranium-containing phase particles in the superconducting matrix. These particles are of approximately spherical geometry with dimensions of around 1 μm. The average size of the nonsuperconducting phase particles in the uranium-doped microstructure is an order of magnitude less than their size in un-doped Nd-123 prepared with excess Nd-422. The critical current density of uranium-doped NdBCO is observed to increase significantly compared to the undoped material.

Item Type: Article
Divisions: Div C > Materials Engineering
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:50
Last Modified: 14 Sep 2017 01:27