MgO/TiN Buffer Layer Structures for Coated Conductor Development on Cu-Based Substrates

A MgO/TiN based multilayer structure suitable as buffer for the development of ReBa₂Cu₃O_7-x (RE = rare earth, Y)-based coated conductors has been developed. The epitaxial growth of TiN film on cube textured substrate was widely studied in terms of structural and morphological properties. TiN films were epitaxially grown on Ni-W substrates in a wide range of deposition condition. The TiN films are compact and dense with smooth surfaces. An MgO film deposited on the top of the TiN layer reproduces the characteristics of the underlying film. In order to test the TiN/MgO structure, a YBCO film was deposited using a SrTiO3 film as cap layer. A Cu-based cube textured tape was employed as substrate, i.e., Ni-50%at. Cu-0.5%at. W. The YBCO film presents a major c-axis orientation with a sharp out-of-plane distribution. Zero-resistance critical temperature of about 85 K was obtained.