An x-ray absorption spectral study of the Ce{sub 2}Fe{sub 17{minus}x}M{sub x} solid solutions, where M is aluminum or silicon (abstract)

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.364680· OSTI ID:544310

Vandormael, D; Grandjean, F ^[1]; Briois, V ^[2]; Middleton, D P ^[3]; Buschow, K H ^[4]; Long, G J ^[5]

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1. Institute of Physics, B5, University of Liege, B-4000 Sart-Tilman (Belgium)
2. LURE, University of Paris-Sud, F-91405 Orsay (France)
3. Philips Research Laboratories, NL-5600 JA Eindhoven (The Netherlands)
4. Van der Waals-Zeeman Institute, University of Amsterdam, NL-1018 XE Amsterdam (The Netherlands)
5. Department of Chemistry, University of Missouri-Rolla, Rolla, Missouri 65409-0010 (United States)

X-ray absorption measurements have been performed at room temperature on the Ce{sub 2}Fe{sub 17{minus}x}Al{sub x} solid solutions, with x=0 to 9, and the Ce{sub 2}Fe{sub 17{minus}x}Si{sub x} solid solutions, with x=0 to 3. The iron K-edge extended x-ray-absorption fine structure results are consistent with the expected changes in the unit cell volume with increasing aluminum and silicon content. X-ray absorption near-edge structure results at the cerium L{sub III} edge reveal a change in the valence state of cerium from a mixture of trivalent and tetravalent in Ce{sub 2}Fe{sub 17} to predominantly trivalent in Ce{sub 2}Fe{sub 17{minus}x}Al{sub x} and Ce{sub 2}Fe{sub 17{minus}x}Si{sub x} as the aluminum and silicon content increases. This change in valence state corresponds to an increasing partial transfer of electron density from the conduction band to the 4f orbital of cerium, a transfer which is in agreement with the increase in the resistivity observed with increasing aluminum and silicon content. The gradual cerium valence change indicates that both aluminum and silicon are, at least in part, covalently bonded to cerium. The increase in bond covalency agrees well with both the preference of the aluminum and silicon for the 18h site in Ce{sub 2}Fe{sub 17}, the site with the maximum number of three rare-earth near neighbors, and the temperature dependence of the Moessbauer spectral isomer shifts in these solid solutions. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 544310
• Report Number(s): CONF-961141--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 81; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTRA
ALUMINIUM ALLOYS
CERIUM ALLOYS
COVALENCE
CRYSTAL STRUCTURE
IRON BASE ALLOYS
ISOMER SHIFT
SILICON ALLOYS
VALENCE
X-RAY SPECTROSCOPY