Article ID Journal Published Year Pages File Type
1819231 Physica C: Superconductivity and its Applications 2009 5 Pages PDF
Abstract

In the present work, La2Zr2O7 (LZO) buffer layers were deposited using pulsed laser deposition (PLD) on various metallic substrates including epitaxial pure Ni on a LaAlO3 (LAO) substrate as well as highly textured Ni–5 at.%W tapes. It is shown that the LZO deposited on pure Ni-buffered LAO exhibits a mixed orientation while LZO on Ni–5 at.%W grows epitaxially. This difference may be explained by the existence of a sulphur superstructure on the surface of Ni–5 at.%W tapes, promoting the epitaxial (0 0 l) nucleation of seed layers. Highly textured YBa2Cu3O7−δ layers were prepared either by using a single buffer layer of LZO or bilayer buffers of CeO2/LZO on Ni–5 at.%W. The superconducting transition temperature (Tc) increases with the LZO thickness, reaching a value of 90 K with a very narrow transition width (1.5 K) for 240 nm thick LZO layers. Inductive Jc measurements at 77 K in self-field show a value of about 0.96 MA/cm2 for the thickest LZO layers, which is comparable to the value observed on standard buffer architectures such as CeO2/YSZ/Y2O3.

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Physical Sciences and Engineering Physics and Astronomy Condensed Matter Physics
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