Improved laser-ablated thin films of NdCeCuO by use of N₂O

Abstract

Thin films of the electron-doped superconductor Nd1.85Ce 0.15CuO4-δ were prepared by laser ablation in O 2 and N2O ambients. Although films prepared in an O 2 ambient need to be reduced to become superconducting, the use of a lower oxygen pressure during deposition produces inferior films. A more metallic character can be obtained by increasing the O2 pressure during deposition. The substitution of N2O for O2 results in films that are superconducting without a separate reduction step, with a sharp transition at about 16 K. A short vacuum anneal at the deposition temperature yields reproducible films with Tc=20 K, without change in the transition width.