Microscopical Study of the Structural Evolution of Sol-gel Derived Buffer Layers for the Integration of YBCO on Biaxially Textured Nickel


Epitaxial buffer layers of Ho20 3on biaxially textured nickel were fabricated using a chelate (acetic acid) solution route as an alternative to the 2-methoxyethanol solution approach, which has demonstrated good texturing characteristics. Plan-view SEM studies of the films as a function of heat treatment temperature have shown that the holmium oxide film pyrolyzes into an open structure with a high level of interconnected porosity before densification, without significant film shrinkage in the thickness direction. Consolidation of the film started around 900'C along the backbone of the open structure and sintering to a dense film of uniform small crystallites (-25 nm) was observed at higher temperature. The as-received nickel tapes displayed significant surface damage with a roughness on the order of 1000 A. Electron backscattering analysis suggests that only 65% of the nickel grains were aligned along the (100) axis within 5'. Finally, STM studies of the nickel substrate have shown that small nickel oxide crystallites were formed on the surface when the substrate is in contact with air.


Materials Science and Engineering

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Article - Conference proceedings

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© 2000 Materials Research Society, All rights reserved.

Publication Date

01 Mar 2000