Synthesis, structure, and magnetic properties of the fullerene-based ferromagnets Eu3C70 and Eu9C70

Taishi Takenobu, Dam H. Chi, Serena Margadonna, Kosmas Prassides, Yoshihiro Kubozono, Andrew N. Fitch, Ken ichi Kato, Yoshihiro Iwasa

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Abstract

Intercalation of C70 with europium affords two kinds of magnetic compounds, a canted antiferromagnet EuxC70 (X ≈ 3) and a ferromagnet ExC70 (x ≈ 9) with transition temperatures (Tc) of 5 and 38 K, respectively. The Curie constants in the paramagnetic phase and the saturation moment in the ferromagnetic phase are both understood by the full moment of Eu2+ for both systems. The structure of Eu3-δC70 (δ ≈ 0.27) is pseudo-monoclinic, derived by a simple deformation of the parent face-centered cubic (fcc) structure. Eu9-δC70 (δ ≈ 0.2) forms an fcc structure, in which cuboctahedral clustering of Eu2+ ions is observed in the enhanced size octahedral holes. The observed Tc of the Eu9-δC70 ferromagnet is comparable to or larger than those of simple binary Eu-based ferromagnets, such as Eu chalcogenides or carbides, despite the low atomic ratio of Eu in the chemical formulas. This can be understood by the short Eu2+-Eu2+ distances and high coordination numbers permitted by the multiple occupation by Eu2+ ions of the expanded octahedral interstitial sites in higher fullerene-based solids.

Original languageEnglish
Pages (from-to)1897-1904
Number of pages8
JournalJournal of the American Chemical Society
Volume125
Issue number7
DOIs
Publication statusPublished - 2003 Feb 15
Externally publishedYes

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ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Takenobu, T., Chi, D. H., Margadonna, S., Prassides, K., Kubozono, Y., Fitch, A. N., Kato, K. I., & Iwasa, Y. (2003). Synthesis, structure, and magnetic properties of the fullerene-based ferromagnets Eu3C70 and Eu9C70 Journal of the American Chemical Society, 125(7), 1897-1904. https://doi.org/10.1021/ja0288690