Correlation between superconducting Tc and hole concentration was investigated in the Bi2Sr2CaCu2O8+δ system. The hole concentration was varied by substituting cations with different valences for Sr or Ca. In order to increase the hole concentration, some samples were annealed at 430°C in 250 bar of oxygen pressure. We find that Tc increases, takes a maximum at the hole concentration corresponding to 0.2-0.3 holes per CuO2 unit, and then decreases, with increasing hole concentration. This correlation is markedly similar to those in the La2-xSrxCuO4 and YBa2Cu3O7-δ systems.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering