Effect of oxygen partial pressure on the crystallization of CeO2 and La2Zr2O7 bi-axially textured thin films

Films of CeO2 and La2Zr2O7 have been formed by metal-organic decomposition and their crystallization studied under different oxygen partial pressures. Single crystalline substrates were use to model the phenomenon: (0 0 1)SrTiO3 (STO) for CeO2 and (0 0 1)LaAlO3 (LAO) for La2Zr2O7. A chemical interaction has been noticed in the case of CeO2/STO above 900 °C, which also depends on the oxygen partial pressure, such an effect was not observed for LZO/LAO. The presence of oxygen, even in traces (10–100 ppm), favors the growth of randomly oriented grains while low oxygen partial pressure provides conditions where the heterogeneous nucleation on the substrate dominates. Once nucleated under low oxygen partial pressure, annealing can be performed under increasing controlled oxygen partial pressure without modification of the texture but with an improved crystallization. Application of this to coated conductors must be restricted in the field where oxidation of the substrate can be avoided.

► Crystallization of CeO2 and La2Zr2O7 films from metal-organic decomposition.
► Oxygen traces during nucleation favors randomly oriented grains.
► Low oxygen partial pressure allows heterogeneous nucleation to dominate.
► Oxygen favors crystallization to develop.
► Oxygen partial pressure is monitored by a mini zirconia sensor.