Abstract
We have found superconductivity in the 90-K range in A with A=La, Nd, Sm, Eu, Gd, Ho, Er, and Lu in addition to Y. The results suggest that the unique square planar Cu atoms, each surrounded by four or six oxygen atoms, are crucial to the superconductivity of oxides in general. In particular, the high in A is attributed mainly to the quasi two-dimensional assembly of the -Ba--Ba- layers sandwiched between two A layers, with particular emphasis in the layers. Higher- oxides are predicted for compounds with bigger assemblies of layers coupled by Ba-layers.
- Received 13 April 1987
DOI:https://doi.org/10.1103/PhysRevLett.58.1891
©1987 American Physical Society