Continuous growth of epitaxial CeO2 buffer layers on rolled Ni tapes by electron beam evaporation

A reel-to-reel, electron beam evaporation system has been developed to continuously deposit epitaxial CeO2 and other oxide buffer layers on meter long-lengths of rolled Ni tapes. The deposition system includes two interconnected electron beam evaporation chambers and a chamber in which as-rolled Ni tape is in situ annealed to develop biaxial texture. An integral reel-to-reel system with tension control enables motion of the tape with little or no plastic deformation. When depositing epitaxial oxides on Ni, the formation of unfavorably oriented NiO needs to be avoided. Oxide-free, {100}[100]-oriented Ni tapes are prepared by control of the partial pressure of H-2 during Ni annealing. In situ annealed rolled Ni tape over 70 cm long and 1 cm wide has been deposited with an epitaxial CeO2 buffer layer. Critical current density as high as 700 000 A/cm(2) at 77 K in self-field has been achieved for TiBa2Cu3O7-x (YBCO) films deposited on short segments of these buffered substrates. X-ray in-plane phi-scans have been performed as a function of length to determine the crystallographic consistency of the epitaxial CeO2 over length. Results of scanning electron microscopy (SEM) examinations of the CeO2 buffer layer microstructure are presented. (C) 1999 Published by Elsevier Science B.V. All rights reserved.