Oxygen-plasma-assisted molecular beam epitaxial growth of the stable oxides of iron

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:560045

Chambers, S A; Gao, Y; Kim, Y J ^[1]

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1. Pacific Northwest National Lab., Richland, WA (United States)

The need to synthesize well-defined, single-crystal surfaces of model minerals is becoming increasingly more critical as the surface science of these materials matures. Magnetite (Fe{sub 3}O{sub 4}) and {alpha}- and {gamma}-hematite (Fe{sub 2}O{sub 3}) are important surfaces for fundamental studies in molecular geochemistry. We have used oxygen-plasma-assisted molecular beam epitaxy (MBE) to synthesize pure, crystallographically well-defined surfaces of these three materials. {alpha}-Fe{sub 2}O{sub 3} has been grown on {alpha}Al{sub 2}O{sub 3} r- c-, and a-plane, and Fe{sub 3}O{sub 4} and {gamma}-Fe{sub 2}O{sub 3} were grown on MgO(100), MgO(110), and {alpha}-Al{sub 2}O{sub 3}(0001). The resulting surfaces, along with their interfaces to small molecules, have been studied by a number of techniques. In general, we find that lattice matching, minimization of film/substrate interface chemistry, matching of surface free energies, oxygen sublattice continuity across the interface, and careful flux control during growth are extremely important for successful epitaxy. High-quality Fe{sub 2}O{sub 3} growth requires oxygen-rich conditions whereas more iron-rich conditions are required for the growth of high-quality Fe{sub 3}O{sub 4}. In this talk, we discuss recent progress in our laboratory in the growth and detailed characterization of these important oxide surfaces and interfaces.

• OSTI ID: 560045
• Report Number(s): CONF-970443--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
HEMATITE
INTERFACES
MAGNETITE
MINERALS
MOLECULAR BEAM EPITAXY
PLASMA