Hydrogen Relaxation Process in HiPco Carbon Nanotubes Studied by Mechanical Spectroscopy

Abstract:

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The first mechanical spectroscopy experiments in HiPco carbon nanotubes from room temperature to 3 K revealed a thermally activated relaxation process at about 25 K for frequencies in the kHz range. The peak is due to the presence of a very mobile species performing about 103 jumps per second at the peak temperature. The activation energy obtained by the peak shift with frequency is Ea = 54.7 meV; the value of the pre-exponential factor of the Arrhenius law for the relaxation time, τ0 = 10-14 s, which is typical of point defect relaxation and suggests that the process is originated by the dynamics of hydrogen or by H complexes. The peak is much broader than a single Debye relaxation process, indicating the presence of intense elastic interactions in the highly disordered bundle structure. There are indications that the relaxation process is governed by a quantum mechanism.

Info:

Periodical:

Solid State Phenomena (Volume 115)

Edited by:

B.M. Darinskii and L.B. Magalas

Pages:

163-168

DOI:

10.4028/www.scientific.net/SSP.115.163

Citation:

R. Cantelli et al., "Hydrogen Relaxation Process in HiPco Carbon Nanotubes Studied by Mechanical Spectroscopy", Solid State Phenomena, Vol. 115, pp. 163-168, 2006

Online since:

August 2006

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Price:

$35.00

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