Keywords
Superconductors
Physics
How to Cite
Abstract
A great number of the actual applications of the superconductivity uses metallic superconductors capable
to transport high current densities. The optimization of the flux pinning in these conductors is extremely
important to increase the critical density current. The design of the microstructure projected to serve as
pinning centers has been presented as one highly promising technique for the optimization of the
transport properties of these materials [1]. However, due to the nanometric dimensions of these artificial
pinning centers, the profiles of heat treatment used for the reaction and formation of the superconducting
phase must be analyzed carefully, considering the distinct distributions and compositions of the
composites (pinning centers + superconducting phase), in comparison with the conventional materials
[2]. In the present work, the objective is to get a methodology for optimization of the heat treatments
profile of diffusion, reaction and formation of the superconducting phases in materials with pinning
centers in nanometric scale. The distribution and the composition of the pinning centers inside of the
superconducting phase were determined by MEV-FEG and MEV+EDS, respectively. The results of
pinning force Fp, and the maximum critical current density that the superconductor can support were
measured under the influence of an applied magnetic field.
References
MATSUMOTO, K., et al. “Effects of artificial pinningcenters on vortex pinning in high-temperature superconducting films” Physica C, vol.426-431, pp. 1091-1095, 2005.
FILLUNGER, H., et al. “Influence of the annealing time of internal tin Nb3Sn strands on the critical current and the magnetization losses” Physica C, vol. 372–376, pp. 1758–1761, 2002.
SUENAGA, M.,. In: SCHWARTZ, B.B., FONER, S. Eds. Superconductor material science- Metallurgy, fabrication and applications. New York: Plenum Press. Cap. 4, p. 201, 1981.
RODRIGUES JR., D. et al. “Properties and flux pinning of Cu-Nb superconductors with nanometric-scale pinning centers”, IEEE Trans. Appl. Superconduct., v. 15, n. 2, pp. 3389-3392, 2005.
RODRIGUES JR, D., “Analysis and optimization of superconducting materials using the modified collective pinning theory,” IEEE Trans. Appl. Superconduct., vol. 9, n. 2, pp.1747-1750, 1999.
FINNEMORE, D. K., Superconducting proximity effect for in situ and model layered systems. In: Foner, S. and Schwartz, B. B., Superconductor Materials Science, Plenum Press, Nova York e Londres, 1981, cap 11.
E. BARZI et al., “Instabilities in Transport Current Measurements of Nb3Sn Strands”, IEEE Trans. Appl. Superconduct., v. 15, n. 2, p. 3364, 2005.
RODRIGUES, C.A., et al. “Development and characterization of Nb3Sn superconductor wire with nanometric-scale pinning centers” Journal of Physics: Conference Series v.43, pp. 43-46, 2006.
GHOSH, A.K., et al. “Investigation of Instability in High Jc Nb3Sn Strands”, IEEE Trans. Appl. Superconduct., v. 15, n. 2, p.3360, 2005.
ZHANG, P.X., et al. “Investigation of multifilamentary Nb3Sn strand for ITER by internal Sn process” Physica C, vol. 445-448, pp. 819-822, 2006.
FILLUNGER, H., et al. “Influence of the heat treatment of internal tin Nb3Sn strands on the critical current and the magnetization losses” Physica C, vol. 357- 360, pp. 1289-1292, 2001.
MACHADO, J. P. B. et al. “Development of (Nb,Ta)3Sn multifilamentary superconductor wire using a novel niobium tube and internal tin method for high current applications” Physica C 408-410, pp. 204-206,2004.
MÜLLER, M., et al. “Unified heat treatment for multifilamentary internal tin and bronze route Nb3Sn strands” Physica C, vol.419, pp. 115-120, 2005.
CURSINO, E. “Desenvolvimento e caracterização de fitas monofilamentares de Ag/Bi2212 texturizadas pelo método de fusão parcial”, dissertação de mestrado, Departamento de Engenharia dos Materiais, FAENQUIL, Lorena, Brazil, 2004.
P. VILLARS, A. PRINCE and H. OKAMATO, Handbook of Ternary Alloy Phase Diagrams, ASM International, vol. 8, 199.5, pp. 9753-9757.
RODRIGUES, C.A. “Desenvolvimento e caracterização de supercondutores de Nb3Sn com centros de apri-sionamento de Cu(Sn) em escala nanométrica”, tese de doutorado, Departamento de Engenharia dos Materiais, FAENQUIL, Lorena, Brazil, 2006.
MÜLLER, H., et al. “Optimization of the heat treatment of Nb3Sn-superconductors” Physica C, vol.401, pp. 325-329, 2004.
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