Multifilamantary Niobium tin superconductor tape

An effective method for the fabrication of multifilamentary Nb3Sn tape has been developed. Filamentary superconductive paths are produced in otherwise standard commercial superconductor tape by the chemical milling of separator slots through the Nb3Sn layer. The present multifilament configuration features a matrix of ten parallel helical superconducting paths along the length of the tape; filament width and interfilament separation are approximately 1.2 mm and 0.4 mm respectively. Thirty-five multifilamentary tapes 0.4 m long were produced. Complete arrays of continuous, fully-defined filaments were reliably formed. Tapes tested as small pancake coils (6-10T) demonstrated the integrity and continuity of the matrix and showed that critical current was sustained in direct proportion to retained superconductor. Interesting behavioral differences resulted from filamentization: critical current anisotropy was reversed, and the slope of the Icversus H curve was reduced. Other tests found qualitative evidence of substantially improved stability in the multifilamentary tape.