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Energy Systems and Technologies for the Coming Century ...

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a c eb d fFig. 7. AFM micrographs of YBCO films from stoichiometric target on different yttria layers.a, b - uni<strong>for</strong>m yttria seeding layer; c, d - template yttria layer of nanoparticles; e, f - bareLSAT substrate. Scan size: a, c, e - 10×10 μm 2 , b, d, f - 2×2 μm 2 . Vertical scale 100 nm.For thin films <strong>the</strong> temperature T c of <strong>the</strong> superconducting transition of <strong>the</strong> Y-enrichedfilms was ~1 K lower than that of a st<strong>and</strong>ard film from <strong>the</strong> stoichiometric target(Fig. 5a), but <strong>for</strong> <strong>the</strong> thick films we observed <strong>the</strong> opposite: <strong>the</strong> T c of <strong>the</strong> Y-enriched filmseven increased, while <strong>for</strong> st<strong>and</strong>ard films it decreased, <strong>and</strong> <strong>the</strong> superconducting transitionbecame broad (Fig. 5b). Probably, <strong>the</strong> pores in <strong>the</strong> Y-enriched films act as routes <strong>for</strong> <strong>the</strong>post-deposition oxygenation of <strong>the</strong> films, while <strong>the</strong> dense film from <strong>the</strong> stoichiometrictarget remains oxygen-deficient.Fig. 8. Fragments of XRD θ/2θ-scans of <strong>the</strong> YBCO films on LSAT (100) substrates withdifferent yttria decoration.Risø International <strong>Energy</strong> Conference 2011 Proceedings Page 245

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