Diffusion of oxygen in amorphous Al{sub 2}O{sub 3}, Ta{sub 2}O{sub 5}, and Nb{sub 2}O{sub 5}

Journal Article · Mon Jul 21 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4889800· OSTI ID:22308461

Tsukui, S. ^[1]; Toda, T.; Tane, M.; Suzuki, T. ^[2]; Ishimaru, M. ^[3]; Nakajima, H. ^[4]

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1. Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai 599-8531 (Japan)
2. The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047 (Japan)
3. Department of Materials Science and Engineering, Kyushu Institute of Technology, Tobata, Kitakyushu, Fukuoka 804-8550 (Japan)
4. The Wakasa Wan Energy Research Center, Tsuruga, Fukui 914-0192 (Japan)

The self-diffusivity of oxygen in amorphous Al{sub 2}O{sub 3} (a-Al{sub 2}O{sub 3}), a-Ta{sub 2}O{sub 5}, and a-Nb{sub 2}O{sub 5} was investigated along with structural analysis in terms of pair distribution function (PDF). The low activation energy, ∼1.2 eV, for diffusion in the oxides suggests a single atomic jump of oxygen ions mediated via vacancy-like defects. However, the pre-exponential factor for a-Ta{sub 2}O{sub 5} and a-Nb{sub 2}O{sub 5} with lower bond energy was two orders of magnitude larger than that for a-Al{sub 2}O{sub 3} with higher bond energy. PDF analyses revealed that the short-range configuration in a-Ta{sub 2}O{sub 5} and a-Nb{sub 2}O{sub 5} was more broadly distributed than that in a-Al{sub 2}O{sub 3}. Due to the larger variety of atomic configurations of a-Ta{sub 2}O{sub 5} and a-Nb{sub 2}O{sub 5}, these oxides have a higher activation entropy for diffusion than a-Al{sub 2}O{sub 3}. The entropy term for diffusion associated with short-range structures was shown to be a dominant factor for diffusion in amorphous oxides.

• OSTI ID: 22308461
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
ALUMINIUM OXIDES
AMORPHOUS STATE
BINDING ENERGY
CONFIGURATION
CRYSTAL DEFECTS
DIFFUSION
DISTRIBUTION FUNCTIONS
ENTROPY
EV RANGE
NIOBIUM OXIDES
OXYGEN IONS
TANTALUM OXIDES
VACANCIES