Influence of nanometer-scale copper filaments in niobium on mechanical and superconducting properties

Abstract Nanometer-scale copper filaments are introduced into niobium as artificial flux pinning centers (APC's) by multiple extrusion. A ribbon-like structure is observed in both niobium and copper at the final wire size. The composite experiences extensive work hardening during mechanical reduction. The pinning force of niobium with APC's is significantly enhanced relative to that of cold worked bulk niobium.