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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, hayashi@ilab.ntt.co.jp
S. Hirono
Affiliation:
NTT Integrated Information & Energy Systems Laboratories Musashino-shi, Tokyo 180, Japan, hayashi@ilab.ntt.co.jp
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, hayashi@ilab.ntt.co.jp
J.-J. Delaunay
Affiliation:
NTT Integrated Information & Energy Systems Laboratories Musashino-shi, Tokyo 180, Japan, hayashi@ilab.ntt.co.jp
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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

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References

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