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Iron Nanoparticles Embedded in Silica Glass: A Computational Study

Published online by Cambridge University Press:  01 February 2011

Peter Kroll
Affiliation:
[email protected], RWTH Aachen, Inorganic Chemistry, Landoltweg 1, Aachen, N/A, Germany
Jens Theuerkauf
Affiliation:
[email protected], RWTH Aachen, Inorganic Chemistry, Landoltweg 1, Aachen, 52056, Germany
Thomas Wieland
Affiliation:
[email protected], RWTH Aachen, Inorganic Chemistry, Landoltweg 1, Aachen, 52056, Germany
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Abstract

We performed electronic structure calculations within density functional theory including ab initio molecular dynamic simulations of isolated Fe13 and Fe55 clusters. We observed the energy preference of icosahedral clusters over cuboctahedrons for both Fe13 and Fe55. The magnetic structure is ferromagnetic for Fe13, but anti-ferromagnetic for Fe55. But isolated clusters exhibit a HOMO-LUMO gap. Subsequently, we embedded the clusters into models of silica glass of different size. For embedded clusters we observed the formation of an iron oxide interface between cluster and dielectric matrix. Though many different models were computed, they show a very homogeneous trend. The magnetization of optimized embedded models is close or larger than the magnetization of free clusters. The small clusters retain their electronic structure around the Fermi-level despite some major distortions.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

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References

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