Patent ID: 7618923

Claim:
A method for making a long superconductor, e.g. a tape or wire, by depositing at least one polycrystalline superconducting compound onto a metallic substrate or onto a buffer layer system on said substrate, characterized by the following steps fabricating said metallic substrate or said buffer layer system to consist of or to contain at least on its surface a microstructure of longitudinally oriented, long grains with a high aspect ratio, a=L par /L per exceeding 1.5, said microstructure being controlled by mechanical, atom-beam, or ion-beam treatment, treating said surface of said metallic substrate or top of said buffer layer to form grooves in a direction of current flow, and epitaxially growing said superconducting compound on said substrate or on a top layer of said buffer layer system to produce a percolation path of long superconducting grains being aligned longitudinally and exhibiting a high aspect ratio such that their projection, being characterized by a length L par parallel to the longitudinal extension of said superconductor and a length L per perpendicular thereto, has an aspect ratio a=L par /L per exceeding 1.5, the total volume V of said long superconducting grains exceeding 10% of the volume of said superconducting compound.