Low temperature oxidation mechanisms of nanocrystalline magnetite thin film

Journal Article · Mon Jan 07 00:00:00 EST 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4772714· OSTI ID:22089671

Bourgeois, F.; Gergaud, P.; Feuillet, G. ^[1]; Renevier, H.; Leclere, C. ^[2]

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1. CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 GRENOBLE, Cedex 9 (France)
2. Grenoble INP Minatec, LMGP, 3 parvis Louis Neel, 38016 Grenoble (France)

A detailed investigation of the mechanisms related to the low temperature oxidation of nanocrystalline magnetite thin films into maghemite is presented. Despite strong differences in the functional properties of these two phases, structural similarities make it difficult to distinguish between them, and to quantify the oxidation process, particularly in the case of nanostructured polycrystalline layers. Contrary to the case of bulk materials or monocrystalline films and particles, the oxidation processes in nanocrystalline thin film have only scarcely been studied. In this work, structural and optical techniques, including X-ray diffraction (XRD), EXAFS/X-ray absorption near edge structure, FTIR, and Raman scattering, have been used to estimate the oxidation rate of magnetite. The overall oxidation reaction rates are discussed in the framework of two limiting cases corresponding to intra grain diffusion and to grain boundary diffusion. SIMS profiling and electrical measurements were also carried out to better assess the oxidation quantification in order to conclude on the predominant oxidation mechanisms in this heterogeneous material. We propose a qualitative model for the structure, in terms of insulating zone distribution, for partially oxidized films.

• OSTI ID: 22089671
• Journal Information: Journal of Applied Physics, Vol. 113, Issue 1; Other Information: (c) 2013 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
DIFFUSION
FOURIER TRANSFORM SPECTROMETERS
GRAIN BOUNDARIES
INFRARED SPECTRA
ION MICROPROBE ANALYSIS
IRON COMPOUNDS
LAYERS
MAGNETITE
MASS SPECTRA
NANOSTRUCTURES
OXIDATION
POLYCRYSTALS
RAMAN EFFECT
RAMAN SPECTRA
THIN FILMS
X RADIATION
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY