Grain boundary networks in RABiTS based YBa2Cu3O7[-delta] coated conductors

This thesis deals with the transport properties and critical current limitations found in YBa2Cu3O7[-delta] coated conductors prepared by the "rolling assisted biaxially textured substrate" (RABiTS) approach. For this purpose a buffer layer system composed of CeO2 and yttria-stabilised zirconia, and subsequently a YBa2Cu3O7[-delta] film were epitaxially grown by pulsed laser deposition on a biaxially textured metallic substrate. The resulting texture of the YBa2Cu3O7[-delta] film is crucial for the achievement of high critical current densities. A propagation of the granular structure of the metallic substrate into the YBa2Cu3O7[-delta] film was detected, which leads to the formation of a YBa2Cu3O7[-delta] grain boundary network and limits the critical current density of the samples. In order to study this limitation, critical current measurements were performed on the prepared samples at different temperatures and magnetic fields, detecting a transition between intergrain and intragrain current limitation that occurs at the so-called crossover magnetic field. The crossover magnetic field was found to shift to lower values as the temperature was increased. It was concluded that the grain boundary network limits the critical current density of the YBa2Cu3O7[-delta] coated conductor only for magnetic fields below the crossover field.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Technische Universität Dresden

Year

2004

Author dc:creator

• Fernández Gómez-Recuero, Laura

Contributors dc:contributor

• Schultz, Ludwig
• Obradors, Xavier
• Wosnitza, Joachim

• Korngrenzennetzwerke
• YBa2Cu3O7[-delta]
• biaxiale Textur
• metallische Substrate
• biaxial texture
• grain boundary networks
• metallic substrates