Abstract: A composite superconductor having both filamentary and film conductors for carrying the pure and impure components of direct current, respectively, or for alternating current, is disclosed, together with a method of making it, and a preferred arrangement for its use in high power transmission lines.

Abstract: A composite multifilament superconducting structure is provided, which includes an elongated substrate-carrying, longitudinally-directed, sputtered discrete filament of an A-15 type intermetallic superconductor. In a preferable procedure, a plurality of spaced, generally longitudinal grooves are formed on the surface of an elongated filamentary substrate, preferably a metal wire. The walls of the grooves on the substrate surface are shaped to undercut the curvilinear surface of the substrate located between two adjacent grooves so that at least some of the wall portions of the grooves are geometrically shadowed during the subsequent sputtering step in which a superconductor is sputtered onto the substrate. In particular, a film of a suitable superconducting intermetallic compound having A-15 crystalline structure, such as Nb.sub.3 Ge, is thereupon sputtered onto the grooved substrate and deposits at the bottom of the grooves and at the surface portions of the substrate between grooves.