Campus Units

Chemistry

Document Type

Article

Publication Version

Published Version

Publication Date

2011

Journal or Book Title

Journal of the American Chemical Society

Volume

133

Issue

17

First Page

6832

Last Page

6840

DOI

10.1021/ja200909r

Abstract

The electronic structures of “Ti9-nFe2+nRu18B8” (n = 0, 0.5, 1, 2, 3), in connection to the recently synthesized Ti9-nFe2+nRu18B8 (n = 1, 2), have been investigated and analyzed using LSDA tight-binding calculations to elucidate the distribution of Fe and Ti, to determine the maximum Fe content, and to explore possible magnetic structures to interpret experimental magnetization results. Through a combination of calculations on specific models and using the rigid band approximation, which is validated by the DOS curves for “Ti9-nFe2+nRu18B8” (n = 0, 0.5, 1, 2, 3), mixing of Fe and Ti is anticipated at both the 2b- and 4h-chain sites. The model “Ti8.5Fe2.5Ru18B8” (n = 0.5) revealed that both Brewer-type Ti−Ru interactions as well as ligand field splitting of the Fe 3d orbitals regulated the observed valence electron counts between 220 and 228 electrons/formula unit. Finally, models of magnetic structures were created using “Ti6Fe5Ru18B8” (n = 3). A rigid band analysis of the LSDA DOS curves concluded preferred ferromagnetic ordering at low Fe content (n ≤ 0.75) and ferrimagnetic ordering at higher Fe content (n > 0.75). Ferrimagnetism arises from antiferromagnetic exchange coupling in the scaffold of Fe1-ladder and 4h-chain sites.

Comments

Reprinted (adapted) with permission from J. Am. Chem. Soc., 2011, 133 (17), pp 6832–6840. Copyright 2011 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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