Matches in UGent Biblio for { ?s ?p More than twenty years ago in a series of amazing discoveries, it was found that a large family of ceramic cuprate materials exhibited superconductivity at temperatures above the boiling point of liquid nitrogen. Imaginations were energized by the thought of applications for zero-resistance conductors cooled with a relatively inexpensive and readily available cryogen. Compared with other cuprates, YBa2Cu3O7-x (YBCO) seems to be the most promising material because of the current carrying ability in a magnetic field and a high current density self-field. This thesis describes the synthesis using water-based precursors of the superconducting phase YBCO both in bulk and in the capacity of a thin layer. In addition, the preparation of a CeO2 layer via a water-based sol-gel method is also discussed. The thesis has focused mainly on the influence of complexing agents and pH on the precursor and the homogeneity of the precursor gels. The concentration of different possible species in solution was first modeled using the existing numerical algorithms. On the other hand, an experimental verification of the calculated theoretical situation was pursued by potentiometric titration. A second part of the thesis provides insights into the characterization of the gels and the formed oxide phases, such as chemical composition, morphology and preferred orientation. The aqueous precursor formulations, consisting of inexpensive and environmentally-friendly starting materials, studied in this thesis can be a viable alternative to the TriFluoroAcetic acid (TFA) precursors or physical deposition methods nowadays used in fabrication of coated conductors.. }
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- aggregation abstract "More than twenty years ago in a series of amazing discoveries, it was found that a large family of ceramic cuprate materials exhibited superconductivity at temperatures above the boiling point of liquid nitrogen. Imaginations were energized by the thought of applications for zero-resistance conductors cooled with a relatively inexpensive and readily available cryogen. Compared with other cuprates, YBa2Cu3O7-x (YBCO) seems to be the most promising material because of the current carrying ability in a magnetic field and a high current density self-field. This thesis describes the synthesis using water-based precursors of the superconducting phase YBCO both in bulk and in the capacity of a thin layer. In addition, the preparation of a CeO2 layer via a water-based sol-gel method is also discussed. The thesis has focused mainly on the influence of complexing agents and pH on the precursor and the homogeneity of the precursor gels. The concentration of different possible species in solution was first modeled using the existing numerical algorithms. On the other hand, an experimental verification of the calculated theoretical situation was pursued by potentiometric titration. A second part of the thesis provides insights into the characterization of the gels and the formed oxide phases, such as chemical composition, morphology and preferred orientation. The aqueous precursor formulations, consisting of inexpensive and environmentally-friendly starting materials, studied in this thesis can be a viable alternative to the TriFluoroAcetic acid (TFA) precursors or physical deposition methods nowadays used in fabrication of coated conductors.".