A study on the effect of the lattice oxygen on the LaNiO_3-x thin films

Metallic conductive LaNiO_3-x films with pseudo-cubic (100) preferred orientation are prepared by RF magnetron sputtering and in situ annealed at 265°C. The experiment results indicate that the grains are of a uniform size, about l0 nm, the lattice oxygen concentration and the electric conductivity of the films decrease near-exponentially as annealing time increases. A reasonable explanation is provided and verified by a computational simulation u-sing the classical electromagnetic theory. Both the simulation and the experimental results illustrate that the films RF-sputtered only in argon are of lattice oxygen inefficiency. In order to improve the electrical conductivity, the oxygen partial pressure should be over 20%.