ARTIFICIAL 2-PHASE NB-TI NANOSTRUCTURES USING POWDER-METALLURGY TECHNIQUES

Several techniques to form artifical high critical current density superconducting Nb-Ti nanostructures have been reported. A drawback to virtually all of these techniques is that they require fabrication strains of 30 or more to reduce the second phase pinning center to the optimum 1-10 nm size at which critical current densities of 10(3)-10(4)A/MM2 are obtained. Here we describe a powder metallurgy process that yields 6020 A/MM2 at 2 T and 1470 A/MM2 at 5 T for an alloy with an upper critical field of approximately 8 T within the same strain space (approximately 13) employed in the conventional Nb-Ti fabrication process.