Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 2: Superconductivity: Conductor Development
TT 2.5: Vortrag
Montag, 27. März 2006, 12:30–12:45, HSZ 02
Development of coated conductors with an elongated grain structure — •R. Hühne, J. Eickemeyer, D. Selbmann, J. Hänisch, L. Schultz, and B. Holzapfel — IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany
The critical current density in RABiTS based coated conductors is limited by the network of small angle grain boundaries up to a texture dependent crossover field. However, YBCO layers with high aspect ratio grains should enable a more effective current transport due to an improved weak link behaviour at the elongated grain boundaries. Recently, cube textured substrates with an elongated grain structure were successfully prepared by specific processing of nickel tapes microalloyed with silver. The aspect ratio of the grains in these tapes was increased from about one to about four. Additionally, epitaxial NiO layers were grown a first buffer on the Ni-Ag substrate using surface oxidation epitaxy (SOE) resulting in a similar texture quality like the tape itself. YBCO layers were prepared afterwards by pulsed laser deposition on the Ni as well as on the NiO using a suitable buffer system. Inductive measurements revealed critical temperatures above 87 K and critical current densities Jc up to 1.6 MA/cm2 at 77 K in zero magnetic field. The anisotropic current transport mechanism was experimentally proven in resistive measurements showing higher Jc-values along the grain elongation compared to the transverse direction.