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Stoichiometry and Magnetic Properties of Iron Oxide Films

Published online by Cambridge University Press:  10 February 2011

D. V. Dimitrov ,
G. C. Hadjipanayis ,
V. Papaefthymiou  and
A. Simopoulos
D. V. Dimitrov
Affiliation:
Department of Physics and Astronomy, University of Delaware, Newark, DE 19716
G. C. Hadjipanayis
Affiliation:
Department of Physics and Astronomy, University of Delaware, Newark, DE 19716
V. Papaefthymiou
Affiliation:
Department of Physics, University of Ioannina, Ioannina, Greece
A. Simopoulos
Affiliation:
NCSR Demokritos, 15310 Aghia Paraskevi, Attikis, Athens, Greece
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Abstract

The stoichiometry, structural and magnetic properties, and Mössbauer spectra of reactively sputtered Fe-O films were studied as a function of the O2 partial pressure during the deposition. By increasing the amount of O2 films with the following crystallographic structures and stoichiometry were fabricated; amorphous Fe-O, mixture of Fe and FeO, offstoichiometric single-phase FexO, mixture of FeO and Fe3O4, single-phase Fe3O4, mixture of Fe3O4 and γ-Fe2O3, mixture of Fe3O4 and α-Fe2O3, and single-phase α-Fe2O3. The Verwey transition in Fe3O4 films was observed in the coercivity versus temperature curve and in the thermomagnetic data. FeO and α-Fe2O3 films showed anomalous ferromagnetic-like behavior, in contrast to their anti ferromagnetic nature in bulk. The unusual magnetic properties were attributed to the formation of clusters of tetrahedraly coordinated Fe3+ ions in FeO and to uncompensated surface spins, in α - Fe2O3 films.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 494: Symposium V – Science & Technology of Magnetic Oxides , 1997 , 89
Copyright
Copyright © Materials Research Society 1998

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References

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