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TT: Fachverband Tiefe Temperaturen

TT 18: Superconductivity: Fabrication and Characterization

TT 18.7: Vortrag

Dienstag, 24. März 2009, 15:45–16:00, HSZ 105

Phase evolution of BaHfO₃ pinning centers in YBCO thin films fabricated with the TFA-MOD process — •Thomas Thersleff, Sebastian Engel, Jens Hänisch, Robert Kluge, Ruben Hühne, Ludwig Schultz, and Bernhard Holzapfel — IFW-Dresden, P.O. Box 270116, 01171 Dresden, Germany

Exploiting the exceptional electrical and magnetic properties of superconducting YBa₂Cu₃O_7−δ (YBCO) coated conductors for the commercial market requires both an economical deposition process as well as a means of enhancing the pinning of magnetic flux lines to increase performance of these materials in applied magnetic fields. Introducing nanosized BaHfO₃ (BHO) particles into a YBCO layer deposited using the well-documented chemical solution deposition route known as TFA-MOD is one way to achieve both of these goals. However, the conversion from a precursor solution to crystalline YBCO is complicated and not fully understood, particularly when nanoparticles are added. This contribution takes a closer look at the phase evolution of these nanoparticles in the TFA-MOD-based process. Films with varying concentrations of BHO particles were quenched at different temperatures during the conversion process. Transport and inductive measurements on the fully reacted samples with BHO particles indicate an increased pinning effect with higher dopant concentrations. X-ray results reveal the formation of BHO particles before YBCO is observed, suggesting they precipitate at the substrate. Finally, FIB cuts and TEM cross-section images provide a robust characterization of these films at various stages of the conversion process.