IMPROVED CRITICAL CURRENT DENSITY AT HIGH MAGNETIC FLUX IN NIOBIUM-TITANIUM-TANTALUM SUPERCONDUCTORS BY ARTIFICIAL PINNING CENTERS

ARTIFICIAL PINNING STRUCTURES PROMISE DRAMATICALLY INCREASED CRITICAL CURRENT DENSITIES IN SUPERCONDUCTORS. FABRICATION AND TESTING FOR LOW CRITICAL TEMPERATURE (TC) MATERIALS IS RELATIVELY FREE OF COMPLICATIONS, AND THE TECHNOLOGICAL AND ECONOMIC IMPACT IS LARGE AND IMMEDIATE. THIS PROJECT COULD DIRECTLY AFFECT U.S. COMPETITIVENESS IN THE LARGE MARKET FOR MAGNETIC RESONANCE IMAGING (MRI) (WHICH IS THE LARGEST COMMERCIAL APPLICATION OF SUPERCONDUCTIVITY) AND COULD ALSO BE READY IN TIME TO SUBSTANTIALLY REDUCE THE COST OF THE SUPERCONDUCTING SUPER COLLIDER DIPOLE AND QUADRUPOLE MAGNETS REQUIRED FOR THE MID-TO-LATE 1990S. PRELIMINARY DESIGNS HAVE ALREADY PRODUCED NEAR RECORD CRITICAL CURRENT DENSITIES (JCS). THE PROBLEM IS THAT THE ENHANCEMENT OF JC THROUGH INCLUSION OF GOOD PINNING MATERIALS IS TRADED OFF AGAINST REDUCTION IN TC AND CRITICAL MAGNETIC FIELD BY POSSIBLE ALLOY AND PROXIMITY EFFECTS. THE PHASE I EFFORT FOCUSES ON NEW PINNING DESIGN AND FABRICATION TO PRODUCE NIOBIUM-TITANIUM-TANTALUM (NBTITA) SUPERCONDUCTORS WHICH WILL HAVE A FACTOR OF 2 INCREASE IN JC PROPERTIES OVER CONVENTIONALLY PROCESSED NBTI SUPERCONDUCTORS.