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Processing of single- and multi-domain YBa{sub 2}Cu{sub 3}O{sub x} bulk materials for levitation applications by Nd{sub 1+x}Ba{sub 2-x}Cu{sub 3}O{sub y} seeding

Description: Melt processing of YBa{sub 2}Cu{sub 3}O{sub x} (Y123) is a well established technique to produce materials for levitation applications. We report our new results on the melt-processing of Y123. To achieve materials with high levitation forces we utilize a seeding technique using Nd{sub 1+x}Ba{sub 2-x}Cu{sub 3}O{sub y-} seeds (Nd123). Two different kinds of Nd13-seeds, one plate-shaped and the other cube-shaped, were developed and used for this study. The microstructures of the levitators depend… more
Date: January 1, 1995
Creator: Todt, V. R.; Sengupta, S. & Miller, D. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fabrication of large domain YBa{sub 2}Cu{sub 3}O{sub x} for magnetic suspension applications

Description: Large domain YBa{sub 2}Cu{sub 3}O{sub x} levitators have been fabricated using a seeded melt processing technique. Depending upon the seed, either a single or five domained sample can be obtained. The grain boundaries separating each domains in the five domain levitator are found to be 90 degrees. Similar levitation forces can be observed for single and five domained samples. After thermal cycling, however, a small decrease in the levitation force of the five domain levitator was observed as a … more
Date: December 31, 1995
Creator: Todt, V.R.; Zhang, X.; Miller, D.J.; Sengupta, S.; Corpus, J. & Gains, J.R. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

From meandering to straight grain boundaries: Improving the structures of artificially-induced grain boundaries in superconducting YBa{sub 2}Cu{sub 3}O{sub y} bicrystals

Description: This paper presents several key aspects of the successful approach to preparing artificially-induced [001] tilt YBa{sub 2}Cu{sub 3}O{sub y} (YBCO) grain boundaries (GBs) with uniform, well-defined structures. The authors have compared the structure of GBs produced in thin film bicrystals and bulk bicrystals, respectively. In the YBCO thin film bicrystals prepared by off-axis magnetron sputtering, meandering rather than planar GBs were generally formed due to the three-dimensional island-shaped … more
Date: August 1, 1997
Creator: Zhang, X. F.; Todt, V. R. & Miller, D. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Nucleation and growth of single- and multiple-domain YBa{sub 2}Cu{sub 3}O{sub x} levitators: Influence of seed crystallography

Description: Large diameter YBa{sub 2}Cu{sub 3}O{sub x} levitators have been fabricated using seeded melt processing. Two types of levitators have been produced: single-domain, obtained using flat NdBa{sub 2}Cu{sub 3}O{sub x} seeds, and five-domain, obtained using cubic NdBa{sub 2}Cu{sub 3}O{sub x} seeds. The difference in these two types of levitators can be attributed to differences in nucleation and solidification processes. In particular, the nucleation of multiple (five) domain levitators may be relate… more
Date: December 31, 1996
Creator: Todt, V. R.; Zhang, X. F. & Miller, D. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Melt-texturing of carbon containing YBa{sub 2}Cu{sub 3}O{sub 7-x}: Influence of processing parameters on microstructure and flux-pinning behavior

Description: A detailed study of the flux-pinning behavior of sintered and melt-textured YBa{sub 2}Cu{sub 3}O{sub 7-x} has been carried out by means of microstructural investigations (optical microscopy, SEM, TEM, EDS, DTA, and XRD) and magnetization measurements. It was found that both microstructure and magnetization behavior strongly depend on the starting material, the production method, and the maximum processing temperature. In our experiments, the critical current density, J{sub c}, increased with in… more
Date: January 1, 1994
Creator: Todt, V.R.; Sengupta, S.; Chen, Y.L.; Shi, Donglu; Poeppel, R.; McGinn, P.J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Fabrication and characterization of melt-processed YBCO

Description: Large domain YBCO are fabricated by using a melt processing technique for magnetic levitation applications. A Nd{sub 1+x}Ba{sub 2{minus}x}Cu{sub 3}O{sub y} seed is used to initiate grain growth and to control the orientation of YBCO grains. Samples as large as 2 inch have been fabricated by utilizing this method. Microstructural studies reveals two distinct regions in these levitators due to different growth mechanism along a/b and c axis. Some initial results on the mass production of these le… more
Date: November 1996
Creator: Sengupta, S.; Corpus, J.; Gaines, J. R., Jr.; Todt, V. R.; Zhang, X. F.; Miller, D. J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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