This is a multiyear experimental research program focused on improving relevant material properties of high-T c superconductors (HTSs) and on development of fabrication methods that can be transferred to industry for production of commercial conductors. The development of teaming relationships through agreements with industrial partners is a key element of the Argonne National Laboratory (ANL) program. Technical Highlights Recent results are presented on YBa 2 Cu 3 O x (Y-123) coated

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... including fabrication by pulsed laser deposition (PLD) and sol-gel techniques. An approach to understanding the critical current density (J c ) of grain boundaries is also presented and a technique is identified for increasing J c . Fabrication of Coated Conductors by Pulsed Laser Deposition In the last quarterly report, we provided details on the deposition conditions for fabricating Y-123 films by PLD. We also reported the dependence of superconducting properties of these films on substrate temperature (T s ) during deposition. A temperature of ≈790°C was found to be optimal for single-crystal substrates. We have continued to optimize PLD deposition and postannealing conditions for producing high-quality Y-123 films. High-quality Y-123 films are now consistently obtained on LaAlO 3 (LAO) and SrTiO 3 (STO) substrates. Y-123 films exhibit T c ≥ 90 K and J c values >3 MA/cm 2 for films ≤0.3 µm thick and 1 MA/cm 2 for films that are >1 µm thick. The J c of Y-123 films made on LAO single-crystal substrates is sensitive to film thickness, decreasing with increasing film thickness, even for films <0.3 µm thick.