[en] The backing consists of at least one layer of thin wires (around 25 μm in dia) of base metals forming the superconductor (niobium or vanadium). The wires are coated with copper or an alloy of copper with metals forming the superconductor, ie., either with Nb, Sn and Ge or with V, Ga and Si. The prepared backing is then tin or gallium coated and annealed at temperatures of 500 to 900 degC during which the superconducting niobium-tin or vanadium-gallium phase is formed. The advantage of the discovery is an increased reaction surface whereby is proportionally increased the critical current of the finished superconductor. Also favourable is the possibility to make a backing of the required shape and the fact that the superconductor need not be stabilized because copper is a better conductor than aluminium which is usually used for stabilization. (Ha)