Microstructure of ZrO2-CeO2 Hetero-Multi-Layer Films Grown on YSZ Substrate
Multi-layer films of pure ZrO{sub 2} and CeO{sub 2} were grown using oxygen plasma assisted molecular beam epitaxy on yttria stabilized zirconia (YSZ) substrates. The microstructure of the film was analyzed using x-ray diffraction (XRD), conventional and high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), energy dispersive x-ray (EDX) elemental mapping, selected area electron diffraction, and dynamical electron diffraction calculations. The deposited pure CeO{sub 2} layers exist in the cubic fluorite structure, and the ZrO{sub 2} layers show a good epitaxial orientation with respect to the CeO{sub 2} layers. However, distinctive forbidden diffraction spots of (odd, odd, even) type were observed on the selected area electron diffraction patterns of the film. Dark-field imaging clearly reveals that these forbidden diffraction spots were contributed solely by the ZrO{sub 2} layers. Dynamical electron diffraction calculation based on the tetragonal phase of unity tetragonality (space group P4{sub 2}/nmc) with oxygen displaced along the c-axis does not match with the experimental pattern. Instead, a diffraction pattern calculated based on a cubic structure (space group P{bar 4}3m) for which the oxygen sub-lattice was displaced along the <111> matches with the experimental data. It is further suggested that the displacement of the oxygen from the ideal (1/4, 1/4, 1/4) position was introduced during the film growth process.
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 15016570
- Report Number(s):
- PNNL-SA-43889; ACMAFD; TRN: US200515%%95
- Journal Information:
- Acta Materialia, Vol. 53, Issue 7; Other Information: PBD: 1 Apr 2005; ISSN 1359-6454
- Country of Publication:
- United States
- Language:
- English
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