Layered copper oxides.

摘要

The present invention provides a layered copper oxide as an insulator for superconductor or as a superconductor, which has a chemical composition represented by the formula of (R,Ce)3Sr2Cu2(M,Cu)O11, wherein R is a rare earth element other than Ce and M is one or both of Pb and Tl, and has a crystal structure comprising a (M,Cu)Sr2(R,Ce)Cu2O7 unit of a TlBa2CaCu2O7(1-2-1-2)type structure and a [(R,Ce)O2]2 unit of a fluorite-type structure alternately put on each other, or a chemical composition represented by the formula of (R,Ce)3Sr2Cu2(M,Cu)O10+z, wherein R is a rare earth element other than Ce, M is one or both of Pb or Tl, and has a crystal structure comprising a (R,Ce)Sr2Cu2(Cu,M)O6+z unit of a YBa2Cu3O6+ delta -type structure and a [(R,Ce)O2]2 unit of a fluorite-type structure alternately put on each other, wherein z is in the range of 0