Electron-doped superconductivity induced by oxygen vacancies in as-grown Sr0.6Ca0.4CuO2?? infinite-layer films

Thin films of the infinite-layer compound Sr0.6Ca0.4CuO2?? have been prepared by off-axis rf magnetron sputtering on SrTiO3 (001). For an optimum level of oxygen vacancy superconductivity was observed (Tc onset = 42 K and Tc(? = 0) = 11 K). Structural and transport data suggesting n-type superconductivity are presented and discussed. Infinite-layer thin films of Sr0.6Ca0.4CuO2??, without trivalent cation doping and showing n-type superconductivity, are reported for the first time.

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