Fabrication of long lengths of YBCO coated conductors using a continuous reel-to-reel dip-coating unit

Abstract

A low-cost, non-vacuum, solution precursor route has been developed to produce epitaxial Gd/sub 2/O/sub 3/ and Eu/sub 2/O/sub 3/ buffer layers and YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) superconductors on biaxially textured metal substrates. On sol-gel Eu/sub 2/O/sub 3/ seed layers with sputtered YSZ and CeO/sub 2/ top layers, a YBCO film with a J/sub c/ of over 1 MA/cm/sup 2/ at 77 K was obtained. On all solution buffer layers (CeO/sub 2//Eu/sub 2/O/sub 3//Ni), YBCO film with a J/sub c/ of 200,000 A/cm/sup 2/ at 77 K was grown using pulsed laser deposition (PLD). Meter lengths of epitaxial and crack-free Gd/sub 2/O/sub 3/ buffer layers were fabricated on cube textured Ni-W (3 at.%) substrates for the first time. High quality YBCO films were deposited on Rolling-Assisted Biaxially Textured Substrates (RABiTS) using a trifluoroacetate (TFA) precursor approach. The precursors were either spin-coated or dip-coated and decomposed in a newly developed fast 3-hour burn-out step followed by post-annealing. In a stationary burn-out route, we have produced 40 cm long crack-free YBCO TFA precursors on RABiTS. On short segments, YBCO films with a J/sub c/ of over 500,000 A/cm/sup 2/ at 77 K were grown on all PLD buffered-Ni substrates (CeO/sub 2//YSZ/CeO/sub 2//Ni).