Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-27T02:06:22.207Z Has data issue: false hasContentIssue false
  • English
  • Français

Magnetic Thin Films of Cobalt Nanocrystals Encapsulated in Graphite-Like Carbon

Published online by Cambridge University Press:  10 February 2011

T. Hayashi ,
S. Hirono ,
M. Tomita ,
S. Umemura  and
J.-J. Delaunay
T. Hayashi
Affiliation:
NTT Integrated Information & Energy Systems Laboratories Musashino-shi, Tokyo 180, Japan, [email protected]
S. Hirono
Affiliation:
NTT Integrated Information & Energy Systems Laboratories Musashino-shi, Tokyo 180, Japan, [email protected]
M. Tomita
Affiliation:
NTT Science and Core Technology Laboratory Group Musashino-shi, Tokyo 180, Japan
S. Umemura
Affiliation:
NTT Integrated Information & Energy Systems Laboratories Musashino-shi, Tokyo 180, Japan, [email protected]
J.-J. Delaunay
Affiliation:
NTT Integrated Information & Energy Systems Laboratories Musashino-shi, Tokyo 180, Japan, [email protected]
Get access

Abstract

Granular thin films consisting of cobalt nanocrystals encapsulated in graphite-like carbon were fabricated by co-deposition of cobalt and carbon with subsequent annealing. The gram size and the crystal structure of the Co-C films depended on the substrate temperature, the carbon concentration, and the annealing temperature. The film deposited with 36 at.% carbon at 200°C consisted of crystalline carbide and hep cobalt, which transformed into hep cobalt and graphite-like carbon by annealing at ≥300 °C. The as-deposited film with a carbon of 46 at.% had an amorphous-like phase and grain sizes of ≤10 nm. By annealing at ≥300°, the amorphous-like phase transformed into cobalt grains with a random stacking structure encapsulated in graphite-like carbon, and the initial size of the grains was unchanged. The saturation magnetization and the in-plane coercivity of these films were also reported.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 475: Symposium M – Magnetic Ultrathin Films, Multilayers, and Surfaces – 1997 , 1997 , 33
Copyright
Copyright © Materials Research Society 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Ruoff, R. S. et al., Science 259, 346 (1993).Google Scholar
2. Tornita, M., Saito, Y, and Hayashi, T., Jpn. J. Appl. Phys. 32, L280 (1993).Google Scholar
3. Saito, Y et al., J. Appl. Phys. 75, 134 (1994).Google Scholar
4. Saito, Y et al., Jpn J. Appl. Phys. 33, L526 (1994).Google Scholar
5. Saito, Y et al., J. Phys. Chem. Solids 54, 1849 (1993).Google Scholar
6. Yoshida, Y et al., J. Appl. Phys. 7 6, 4533 (1994).Google Scholar
7. McHenry, M. E. et al., Phys. Rev. B 49, 11358 (1994).Google Scholar
8. McHenry, M. E., Brunsma, E. M., and Majetich, S. A., IEEE Trans. Mag. 31, 3787 (1995).Google Scholar
9. Murdock, E. S., Simmons, R. F., and Davison, R., IEEE Trans. Mag. 28, 3078 (1992).Google Scholar
10. Hayashi, T. et al., Nature 381, 772 (1996).Google Scholar
11. Delaunay, J.-J. et al., submitted to J. Appl. Phys.Google Scholar
12. Nagakura, S., J. Phys. Soc. Jpn. 16, 1213 (1961).Google Scholar
13. Liuetal, B. X.., Phys. Stat. Sol. (a) 128, K71 (1991).Google Scholar
14. Konno, T. J. and Sinclair, R., Acta Metall. Mater. 42, 1231 (1994).Google Scholar
15. Kittel, C., Introduction to Solid State Physics, 5th ed. (John Wiley & Sons, Inc., New York, 1976), p. 28.Google Scholar
16. Cardellini, F. and Mazzone, G., Phil. Mag. A 67, 1289 (1993).Google Scholar
17. Tajima, S. and Hirano, S., J. Matel. Sci. Lett. 11, 22 (1992).Google Scholar
18. Kazama, N., Heiman, N., and White, R. L., J. Appl. Phys. 49, 1706 (1978).Google Scholar
19. Kobayashi, T. et al., J. Appl. Phys. 64, 3157 (1988).Google Scholar
20. Hamilton, H. J., Mag. Soc. Jpn, 18, Suppl., 171 (1994).Google Scholar