Patent ID: 8105981

Claim:
A superconducting member comprising: a sapphire R face substrate; a buffer layer provided on at least one surface of the sapphire R face substrate; and a superconducting layer having a thickness of not less than 350 nm and not more than 1000 nm provided on the buffer layer, wherein the buffer layer is formed of grain lumps of an oxide, the nearest neighbor distance between the oxygen atoms constituting a crystal face of the oxide parallel to the substrate surface is not more than 0.2705 nm, not less than 90% of grain lumps have a grain diameter of not less than 20 nm and not more than 70 nm, not less than 90% of the grain lumps satisfy a requirement of 5 nm ≦D−d ≦20 nm wherein D represents a maximum thickness of the grain lump, and d represents a thickness of the grain lump in its part adjacent to other grain lump.