Formation of YBa sub 2 Cu sub 3 O sub 7--x Thick Films by a Diffusion Process Between Y sub 2 BaCuO sub 5 and (BaCuO sub 2 , CuO)

• Published in: Superconductor science & technology 1990-08, Vol.4 (1S), p.S358-S360
• Main Authors: Freeman, P A, Ozkan, N, Honneyball, P D, Glowacki, B A
• Format: Article
• Language: English
• ISSN: 0953-2048

The preparation of thick films of YBa sub 2 Cu sub 3 O sub 7--x by diffusion between Y sub 2 BaCuO sub 5 substrates and a surface layer of a barium cuprate mixture (BaCuO sub 2 , CuO) was investigated. The influence of the substrate microstructure and density on the morphology and properties of the diffusion layer were determined by scanning microscopy and transport current measurements. From these investigations it was concluded that an increase in the density of the substrate did not result in an improvement in the transport critical current density of the 123 diffusion layer. Since it is not clear, at this stage, how the current is distributed throughout the different regions of the diffusion layer and why, after densification of the 211 substrate, the major phase formed consisted of a mixture of 123 and CuO, further investigations of the relationship between the microstructure of the diffusion layer and the critical current are considered necessary. Photomicrographs. 2 ref.--AA