Buffer layer structure based on doped ceria for providing optimized lattice match with a YBCO layer in a conductor

A conductor structure comprising:

• a metallic substrate tape over which there is provided at least one buffer layer comprising a CeO2 layer doped with a dopant, and having a superconductive layer of YBCO on said CeO2 layer,
• wherein said at least one buffer layer comprises:
• said doped CeO2 layer which is a lattice matching layer,
• a first layer, between said metallic substrate and said lattice matching layer, being a diffusion barrier against said metallic substrate, and
• a second layer, between said first layer and said lattice matching layer, which is bi-axially textured for transferring its texture to said YBCO layer at a proper deposition temperature, said second layer being an MgO layer having a thickness substantially less than or equal to 10 nm,
• wherein said YBCO layer has a thickness substantially more than or equal to 1 μm and exhibits high current density values.