Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 12: Symposium “Coated HTS Conductors”
TT 12.9: Vortrag
Dienstag, 27. März 2007, 12:15–12:30, H20
Artificial pinning centers in YBa2Cu3O7−x thin films created by nanoparticles from the gas phase — •Maria Sparing, Elke Backen, Thomas Freudenberg, Jörg Acker, Ruben Hühne, Ludwig Schultz, Bernd Rellinghaus, and Bernhard Holzapfel — IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany
The critical current density in YBa2Cu3O7−x (YBCO) thin films, which limits their application in high magnetic fields, can be enhanced by the introduction of artificial pinning centers as, e.g., provided by nanoparticles. An inert gas phase condensation process was used to prepare Y2O3 nanoparticles from an yttrium target by DC magnetron sputtering. With this method, both the size distribution and the areal density of the particles as determined from TEM investigations are independently controlled during deposition. Particles with a mean diameter of about 8 nm were deposited on SrTiO3 substrates, which are terminated by TiO2 through etching with BHF solution and subsequent annealing in 1 atm O2 at 900∘C. The behavior of the particles on the substrate at varying temperatures in an O2 atmosphere of 0,7 mbar (YBCO deposition conditions) was studied by AFM and ICP-MS. A 300 nm thin YBa2Cu3O7−x layer was deposited onto the likewise pre-coated substrates by off-axis pulsed laser deposition. Both inductive and resistive transport measurements at 77K in magnetic fields of up to 9 T reveal the influence of the particles on the superconducting properties of YBa2Cu3O7−x.