Abstract
We have discovered that the doping and subsequent annealing in reducing atmosphere give rise to 24-K superconductivity in the -type structure with sheets of Cu-O squares. In contrast to the previously reported high- cuprates, the charge carriers in the new superconductors are doped electrons, not holes; this was confirmed by the measurements of Hall and Seebeck coefficients as well as by chemical analysis of the effective copper valence. An anomalous dependence of on the concentration of doped electrons is shown for these electron-doped superconducting suprates.
- Received 30 January 1989
DOI:https://doi.org/10.1103/PhysRevLett.62.1197
©1989 American Physical Society