Coupling current loss reduction in cable-in-conduit superconductors by thick chromium oxide coating

Abstract

It is known, that the coupling current losses in cable-in-conduit superconductors can be reduced by a Cr surface coating of the multifilament wires of the cable. Here we have measured for the first time, how a double layer of crystalline Cr and {\\em thick} amorphous Cr oxide reduces the coupling losses. Both layers were successively electrolytically deposited on the surface of the NbTi/Cu multifilament wires. We find that the loss reduction efficiency of this Cr/Cr-oxide double layer is superior to only a Cr layer or an oxidized Cu surface.