We have found superconductivity in the 90-K range in ABa2Cu3O6+x 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 Tc in ABa2Cu3O6+x is attributed mainly to the quasi two-dimensional assembly of the CuO2-Ba-CuO2+x-Ba-CuO2 layers sandwiched between two A layers, with particular emphasis in the CuO2+x layers. Higher-Tc oxides are predicted for compounds with bigger assemblies of CuO2 layers coupled by Ba-layers.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)