Improved superconducting critical current density in modified jelly roll Nb/sub 3/Sn by the application of niobium (Nb) diffusion barriers

摘要

One of the limiting factors of high field magnets is the overall current density available in the high field region. We report a 40% increase in the critical current density of the non-Cu of Modified Jelly Roll (MJR) Nb/sub 3/Sn wires. The increase occurs when niobium diffusion barriers are substituted for the standard vanadium diffusion barriers. The Nb/sub 3/Sn J/sub C/ is also shown to increase when vanadium is removed from the wire. The effective filament diameter of the wire increases only slightly and depends linearly on the MJR diameter. Niobium diffusion barriers are found to improve the RRR of the wire relative to vanadium diffusion barriers.