Electron-doped superconductivity in Sr1−xCaxCuO2−δ infinite-layer thin films

Thin films of infinite-layer compound Sr1−xCaxCuO2−δ have been prepared by rf magnetron sputtering. For an optimum level of oxygen vacancy superconductivities were observed ( T c onset =42 and 50 K, T c (ρ=0) =11 and 20 K). Structural and transport data suggest that the doping mechanism is electron-type. The superconducting transitions were also confirmed by ac susceptibility. Further increase of doping showed to destroy superconductivity.