Letter | Published:

Ferromagnetism of a graphite nodule from the Canyon Diablo meteorite

Abstract

There are recent reports of weak ferromagnetism in graphite1,2 and synthetic carbon materials3 such as rhombohedral C60 (ref. 4), as well as a theoretical prediction of a ferromagnetic instability in graphene sheets5. With very small ferromagnetic signals, it is difficult to be certain that the origin is intrinsic, rather than due to minute concentrations of iron-rich impurities. Here we take a different experimental approach to study ferromagnetism in graphitic materials, by making use of meteoritic graphite, which is strongly ferromagnetic at room temperature. We examined ten samples of extraterrestrial graphite from a nodule in the Canyon Diablo meteorite. Graphite is the major phase in every sample, but there are minor amounts of magnetite, kamacite, akaganéite, and other phases. By analysing the phase composition of a series of samples, we find that these iron-rich minerals can only account for about two-thirds of the observed magnetization. The remainder is somehow associated with graphite, corresponding to an average magnetization of 0.05 Bohr magnetons per carbon atom. The magnetic ordering temperature is near 570 K. We suggest that the ferromagnetism is a magnetic proximity effect induced at the interface with magnetite or kamacite inclusions.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

References

  1. 1

    Esquinazi, P., et al. Ferromagnetism in oriented graphite samples. Phys. Rev. B 66, 0244429 (2002)

  2. 2

    Höhne, R. & Esquinazi, P. Can carbon be ferromagnetic? Adv. Mater. 14, 753–756 (2002)

  3. 3

    Makarova, T. L. Magnetism of carbon-based materials. Studies of High-Tc Superconductivity (ed. Narlikar, A.) Vol. 44–45 (Nova Science, New York, in the press)

  4. 4

    Makarova, T. L. et al. Magnetic carbon. Nature 413, 716–718 (2001)

  5. 5

    Baskaran, G. & Jafari, S. A. Predicting a gapless spin-1 neutral collective mode branch for graphite. Phys. Rev. Lett. 89, 016402 (2002)

  6. 6

    Allemand, P. M. et al. Organic molecular soft ferromagnetism in a fullerene C60 . Science 253, 301–303 (1991)

  7. 7

    Mrzel, A. et al. Ferromagnetism in a cobaltocene-doped fullerene derivative below 19 K due to unpaired spins on fullerene molecules. Chem. Phys. Lett. 298, 329–334 (1998)

  8. 8

    Moehlecke, S., Ho, P. C. & Maple, M. B. Coexistence of superconductivity and ferromagnetism in the graphite-sulfur system. Phil. Mag. B 82, 1335–1347 (2002)

  9. 9

    Murata, K., Ushijima, H., Ueda, H. & Kawaguchi, K. A stable carbon-based organic magnet. J. Chem. Soc. Chem. Commun. 7, 567–569 (1992)

  10. 10

    Grady, M. M. Catalogue of Meteorites, 5th Edn 89–90 (Natural History Museum, London, 2000)

  11. 11

    Papike, J. J. (ed.) Planetary Materials (Reviews in Mineralogy Vol 35, The Mineralogical Society of America, Washington DC, 1998)

  12. 12

    González, J., Guinea, F. & Vozmediano, M. A. H. Electron-electron interactions in graphene sheets. Phys. Rev. B 63, 134421 (2001)

  13. 13

    Wakabayashi, K., Jujita, M., Ajiki, H. & Sigrist, M. Magnetic properties of nanographites at low temperature. Physica B 280, 388–389 (2000)

  14. 14

    Harigaya, K. The mechanism of magnetism in stacked nanographite: theoretical study. J. Phys. Condens. Matter 13, 1295–1302 (2001)

  15. 15

    Kelly, B. T. Physics of Graphite (Applied Science, London, 1981)

  16. 16

    Coey, J. M. D. & Venkatesan, M. Half-metallic ferromagnets; the example of CrO2 . J. Appl. Phys 91, 8345–8350 (2002)

  17. 17

    Alphenaar, B. W., Tsukagoshi, K. & Ago, H. Spin electronics using carbon nanotubes. Physica E 6, 848–851 (2000)

  18. 18

    Brett, R. & Higgins, G. T. Cliftonite: A proposed origin and its bearing on the origin of diamonds in meteorites. Geochim. Cosmochim. Acta 33, 1473–1484 (1969)

Download references

Acknowledgements

We thank M. Viret, F. Guinea and S. Sanvito for discussions. This work was supported by Science Foundation Ireland.

Author information

Competing interests

The authors declare that they have no competing financial interests.

Correspondence to J. M. D. Coey.

Rights and permissions

Reprints and Permissions

About this article

Further reading

Figure 1: The Canyon Diablo graphite nodule at increasing magnifications.
Figure 2: Typical room-temperature curve of magnetization σ against applied field µ0H for graphitic material from the Canyon Diablo meteorite.
Figure 3: Typical X-ray diffraction pattern for graphitic material from the Canyon Diablo meteorite.
Figure 4: Ferromagnetic phase analysis of samples of graphitic material from the Canyon Diablo meteorite.

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.