Crystal Structure of the 80 K Superconductor YBa sub 2 Cu sub 4 O sub 8

Recently a new Y-Ba-Cu-O superconducting oxide has been prepared as distinct phase in thin films. The new phase was first seen as a defect structure in bulk samples of YBa sub 2 Cu sub 3 O sub 7 and found to contain an additional copper layer. The proposed defect structure has a c-axis spacing of ~27angstroms and a cation ratio of YBa sub 2 Cu sub 4.