INCREASING CRITICAL CURRENT DENSITIES IN HIGH-TC SUPERCONDUCTORS

RECENT ADVANCES IN HIGH TEMPERATURE SUPERCONDUCTIVITY BROUGHT A NEW EXCITEMENT TO PHYSICAL SCIENTISTS THROUGHOUT THE WORLD. THIS EXCITEMENT HAS BEEN TEMPERED BY THE REALIZATION THAT DIFFICULT PROBLEMS NEED TO BE SOLVED BEFOREEXTENSIVE PRACTICAL USE CAN BE MADE OF THESE REVOLUTIONARY DISCOVERIES. FOREMOST AMONG THESE PROBLEMS, AND THE ONE WHICH IS ADDRESSED IN THIS PROPOSAL, IS THE ABILITY TO ACHIEVE ADEQUATE CURRENT DENSITIES IN MODERATE MAGNETIC FIELDS IN THE HIGH-T MATERIALS. THE MAJOR SOURCE OF THE "WEAK LINK" BEHAVIOR IN POLYCRYSTALLINE MATERIALS IS POOR INTER-GRAIN CONTACTS. WE SEEK TO LARGELY ELIMINATE THESE WEAK LINK INTER-GRAIN CONTACTS BY PRODUCING A NOVEL MORPHOLOGY WHEREIN THE GRAIN BOUNDARY COMPOSITION IS MODIFIED BY THE PRESENCE OF NANOMETER FILMS OF SILVER.