Fabrication of Y1-xRExBa2Cu3Oy films on single crystalline substrates and IBAD buffered metallic tapes by advanced TFA-MOD process

We fabricated Y1-xSmxBa2Cu3Oy and YSmxBa2Cu3Oy (YSmBCO) films on SrTiO3 (STO) single crystalline substrates and IBAD buffered metallic tapes (PLD-CeO2/IBAD-GZO/Hastelloy) by the advanced TFA-MOD process by mixing TFA salts of Y, Sm, Ba and Cu naphthenate, and tried to improve the superconductivity properties compared with those of the pure YBa2Cu3O7-delta (YBCO). As a result, J(c) values of Y1-xSmxBa2Cu3Oy films With x = 0.05 or 0.3, which were fabricated on STO substrates, were improved under the high magnetic fields compared with those of the YBCO without substitution. However, Sm segregation was detected near the STO substrate which was obtained by the TEM-EDS (transmission electron microscopy-energy-dispersive X-ray spectroscopy) analysis. On the other hand, Y1-xSmxBa2Cu3Oy films with x = 0.05 and YSmxBa2Cu3Oy films with x = 0.3, which were fabricated on IBAD buffered metallic substrates, also improved I-c value under the high magnetic fields compared with those of the YBCO without substitution. Moreover, from the TEM-EDS analysis, Y or Sm segregation was not found. The difference in the Sm segregation behavior between the film on STO and CeO2 buffered substrates could be explained by the difference in the ratios of the misfit parameters between YBCO/substrate and SmBCO/substrate. Additionally, it was considered that the above phenomenon might be unique in the MOD system and could not be observed in the PLD system, because of the difference in the crystal growth mechanism. In the film Of YSm0.3Ba2Cu3Oy, we observed the grains Of (Y, SM)(2)O-3 and (Y, SM)(2)Cu2O5 by TEM observation. We will further investigate the origin of pinning centers. (c) 2006 Elsevier B.V. All rights reserved.