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The j C (B) dependence at 50 K for the Y-enriched films and for the standard film from thestoichiometric target are shown in Fig. 6. The standard film has a rather high j C (0 T),4.5×10 6 A/cm -2 (about 2×10 6 A/cm -2 at 77 K), but all Y-enriched films show higher j C .The j C (B) dependence remains almost the same with increasing thickness of the film,proving the preservation of the film structure during film growth.3.3 YBCO thin films on yttria decorated substratesYBCO thin films (~240 nm) were simultaneously deposited from the stoichiometrictarget on two LSAT samples with different yttria decoration and on a reference bareLSAT substrate. The morphology of the obtained samples is shown in Fig. 7. Largeelongated particles are present on the surfaces of the films on yttria layers (Fig. 7a, c).The particles are oriented along two orthogonal directions on the film surfaces, suchbehavior is typical for a-oriented particles. This supposition, though, is not confirmed bythe XRD measurements. Peaks of a-orientation are absent for the YBCO film on atemplate layer of nanoparticles (Fig. 8). A weak peak from an a-oriented part of the filmis observed only for the film on a uniform yttria layer (top curve, Fig. 8), and, probably,corresponds to the small elongated particles on the film surface (Fig. 7b), that are rare onAFM micrographs of other films.The crystal structure of the c-oriented grains seems to be of higher quality for the filmson yttria layers: the peaks on the XRD θ/2θ-scans are smeared for the YBCO film on abare LSAT substrate, while clear K α1 /K α2 splitting can be seen on both other curves(Fig. 8, left). The reason is strain, for films on yttria layers δd/d = 0.3%, while on a baresubstrate it increases to 0.5%. The c lattice constant is the same for all three films andequals to 11.673 ±0.005 Å. A small c lattice constant implies a high critical temperature;indeed, all three films showed very high T c , 91.4-91.8 K. The YBCO film on a baresubstrate showed both the lowest T c and the widest superconducting transition (Fig. 9).As the c lattice constant in the films does not differ, this variation in superconductingtransition should be attributed to the difference in lattice perfection.Fig. 9. AC susceptibility curves for YBCO films deposited from a stoichiometric targeton LSAT substrates with yttria decoration. Solid line: bare LSAT substrate; dashed line:uniform yttria layer; dotted line: template yttria nanoparicles layer.Risø International Energy Conference 2011 Proceedings Page 246