A. Llordes

Publications (3)3.12 Total impact

• Source

  Available from: Elena Bartolomé

  Article: Vortex Dynamics in Nanostructured TFA-Grown YBCO Films Studied by Ac Susceptibility

  E. Bartolome, A. Palau, A. Llordes, M. Gibert, T. Puig, X. Obradors
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  ABSTRACT: Different successful approaches have recently merged to create artificial pinning centers in YBCO, in the quest to reach coated conductors with higher current performances. We have investigated by ac susceptibility how the different defects affect vortex pinning at high magnetic fields and temperatures, close to the irreversibility line. We analysed the ac response of different sorts of nanostructured YBCO films grown by the chemical solution growth TFA-route: YBCO-BaZrO₃ and YBCO-Y₂O₃ nanocomposites, and YBCO films with additional defects introduced by substrate nanodecoration. The non-linear Bean dynamic regime was studied in order to determine the field dependence of the effective energy barrier for thermally activated flux motion, U _e( H ). Results evidence that BaZrO₃ and Y₂O₃ nanocomposites present peculiar field dependences that may be ascribed to the larger strong-isotropic pinning contribution induced by the isotropic microstrain emerging from the nanoparticles in the YBCO matrix.
  IEEE Transactions on Appiled Superconductivity 07/2011; · 1.04 Impact Factor
• Article: Pinning Landscape Analysis in YBCO Films With Epitaxial and/or Non-Coherent BZO Nanoparticles

  A. Palau, A. Llordes, M. Gibert, T. Puig, A. Pomar, X. Obradors
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  ABSTRACT: The effect of different kind of BaZrO₃ (BZO) nanoparticles on the pinning landscape of YBCO thin films have been investigated. We have correlated the microstrain of the YBCO nanocomposites with the presence of non-coherent and epitaxial BZO nanoparticles. Isotropic and anisotropic pinning contributions have been analyzed by means of angular transport critical current measurements. We show that very high enhancement of isotropic Jc is obtained due to the presence of non-coherent BZO nanoparticles, which can be correlated with an enhancement of the microstrain and a reduction of the anisotropy. Moreover, the contribution of epitaxial interfacial nanoparticles, which enhances the anisotropic Jc component along the c-axis have been also identified.
  IEEE Transactions on Appiled Superconductivity 07/2011; · 1.04 Impact Factor
• Article: Enhanced Vortex Pinning in YBCO Coated Conductors With BZO Nanoparticles From Chemical Solution Deposition

  A. Pomar, V.R. Vlad, A. Llordes, A. Palau, J. Gutierrez, S. Ricart, T. Puig, X. Obradors, A. Usoskin
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  ABSTRACT: We present our latest results on the growth of chemical solution deposited YBa₂Cu₃O₇ - BaZrO₃ nanocomposites on metallic substrates. All chemical ^TFAYBCO-BZO/^MODCZO/^ABADYSZ/SS tapes with J_c(77K,sf) = 1.7 MA/cm² have been achieved with weaker field dependence of J_c than that of standard ^TFAYBCO tapes. Angular resolved measurements show isotropic enhancement of vortex pinning due to the presence of randomly oriented BZO nanoparticles in the YBCO matrix. Chemical routes are thus a promising way to efficiently increase vortex pinning in coated conductors and improve their capabilities for high field applications.
  IEEE Transactions on Appiled Superconductivity 07/2009; · 1.04 Impact Factor