In this letter we show thatSrCuO2/BaCuO2andCaCuO2/BaCuO2based artificial structures of very good crystallographic quality can be grown by pulsed laser deposition. We demonstrate that the most important parameters which determine the superconductive properties are the chemical composition, the oxygen growth pressure, and theCO2contamination. A major difference is found in the behavior of resistivity between films containing Sr and Ca, respectively. Namely [BaCuO2]2/[SrCuO2]nfilms never show any trace of superconductivity, while [BaCuO2]2/[CaCuO2]nfilms result in having, for growth oxygen pressuresPO2⩾0.2 mbar, a full transition withTc(zero resistance) up to 46 K. Furthermore we demonstrate that even a tiny amount ofCO2in the oxygen growth atmosphere can suppress completely the superconducting properties of these artificial structures. ©1997 American Institute of Physics.