Preparation of Ni-based multilayered tape and its potential application for the coating of YBa 2Cu 3O 7− δ

Abstract

Pd and Ag were successively vacuum-deposited on textured Ni-alloys to form multilayered tapes, Ni-alloy/Pd (2000 Å)/Ag. Pole-figure analysis and orientation density function (ODF) calculations show that, with the aid of a Pd buffer layer, Ag can grow epitaxially to inherit the cubic texture, {100}〈001〉, of the Ni-alloy substrates. However, Ag deposited directly on the Ni substrate forms a polycrystalline film without preferred orientation. This fact suggests that Pd, which is soluble in both Ni and Ag, is an indispensable medium for the epitaxial growth of Ag on Ni. Instead, Ag is insoluble in Ni; it is the site-equivalent for Ag depositing at the initial stage; thus, no epitaxy can be expected. The application of multilayered tapes for the coating of YBa 2Cu 3O 7− δ (YBCO) superconductor was examined by the use of pulsed laser deposition (PLD). It was found that the thickness of the Ag layer and the substrate temperature during PLD are the main factors affecting the properties of YBCO films.