9408474 Markiewicz The feasibility of enhancing critical currents in bulk polycrystalline samples of high temperature superconductors, via a process of biaxial alignment, will be explored, with primary emphasis on a europium-barium-copper-oxide superconductor. The quality of intergranular junctions produced by a variety of annealing techniques will be examined by studying critical currents, susceptibility, junction noise, high resolution transmission and scanning transmission microscopy studies of grain boundaries, and microscopic detection of the critical currents associated with individual grain boundaries. Alternative approaches for maintaining oxygen stoichiometry in the densified materials will be explored. Detailed pole figure analyses will be undertaken. Enhancement of critical currents by pinning (second phase inclusions, irradiation damage) will be explored. % % % % To reach the full potential of the new high critical temperature superconductors for application in magnets and energy transmission, superconductor wires or tapes must be able to carry large currents at the temperature of liquid nitrogen and must be manufacturable at reasonable cost. This program explores in depth the physical parameters controlling a new fabrication process which has the potential for greatly enhanced critical currents by reducing or eliminating harmful grain boundary mismatch. In this process small grains are aligned both magnetically and mechanically into a "brick-wall" like network, which is then consolidated by heat treatments to form a high-density material. ***
