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Magnetization results of YBa2Cu3O7−d films processed with interlayers of CeO2 inclusions are presented. Unexpected flux pinning results that are different from previous observations with nanoparticulate layered inclusions were observed. Flux pinning was found to be in some cases either slightly improved at either low fields <0.5T or in other cases at high fields >8T although degraded, sometimes severely, at interim magnetic fields. Most unexpectedly, the pinning performance of the various samples rapidly converges as the temperature is reduced from 77 to 65K, causing all films to have similar Jc(H) behavior at 65K even though dramatically different at 77K.

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this bu den estimate or any other aspect of this collection of information, including suggestions for reducing this burden, This is a work of the U.S. Government and is not subject to copyright protection in the United States. ABSTRACTNanoparticle dispersions of various phases were added to YBa2Cu307, (YBCO or 123) thin films by multilayer pulsed laser deposition, to determine their effect on flux pinning. The different pinning materials examined include Y2BaCu05 (Y211 or green-phase), La2BaCu05 (La211 or brown-phase),Y 203, Ce02, and MgO, with lattice constant mismatches varying from 0.5% to 12% with respect to YBCO. Y211 and Y203 provided significant pinning increases at temperatures of 65 K and 77 K, however other phases provided enhancements only at 65 K (for Ce0 2 and La211) for limited range of applied field strengths. An interesting correlation between T e transition widths and pinning strengths was observed. The additions produced markedly different nanoparticle and film microstructures,as well as superconducting properties. SUBJECT TERMS

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