Structure and magnetic properties of iron nanowires encased in multiwalled carbon nanotubes

Structure and magnetic properties of iron nanowires encased in multiwalled carbon nanotubes

By using X-ray diffraction, transmission electron microscopy, ferromagnetic and electron paramagnetic resonances, Fe-filled multiwalled carbon nanotubes were studied. The iron within the nanotubes was found to be in three phases: the austenite γ-Fe is located at the top of the nanotubes, while the f...

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Bibliographic Details
Published in:Acta materialia Vol. 55; no. 5; pp. 1769 - 1778
Main Authors: Shpak, A.P., Kolesnik, S.P., Mogilny, G.S., Petrov, Yu.N., Sokhatsky, V.P., Trophimova, L.N., Shanina, B.D., Gavriljuk, V.G.
Format: Journal Article
Language:English
Published: Oxford Elsevier Ltd 01-03-2007
Elsevier Science
Subjects:
Applied sciences
Carbon nanotubes
Cementite
Eutectoid reactions
Exact sciences and technology
Ferrite
Ferromagnetic resonance
Ferromagnetism
Iron
Metals. Metallurgy
Multi wall carbon nanotubes
Nanotubes
Nanowires
Transmission electron microscopy
X-ray diffraction
Ferromagnetic resonance
Carbon nanotubes
X-ray diffraction
Iron
Transmission electron microscopy
X ray diffraction
Magnetic properties
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Summary:By using X-ray diffraction, transmission electron microscopy, ferromagnetic and electron paramagnetic resonances, Fe-filled multiwalled carbon nanotubes were studied. The iron within the nanotubes was found to be in three phases: the austenite γ-Fe is located at the top of the nanotubes, while the ferrite α-Fe and cementite θ-Fe 3C are found close to the substrate. The morphology of the α + θ mixture suggests that the eutectoid reaction γ → α + θ occurs. Two ferromagnetic signals were observed and identified as those belonging to ferrite and cementite. Ferromagnetic signals revealed a surprising temperature dependence: with decreasing temperature, their integral intensity decreases nearly linearly, and the signals disappear at temperatures below 70 K. Possible reasons for this behaviour are discussed. Two paramagnetic signals appear at low temperatures. Based on their temperature behaviour and on the values of the g-factors, the first signal is related to localized spin moments and the second one to free electrons.
Bibliography:ObjectType-Article-2
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content type line 23
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2006.10.039