Naslov
Thermodynamic investigation of He4 adsorption in C-SWNT bundles

Autori
Biljaković, Katica

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Bulletin of the American Physical Society: March Meeting, Vol. 49, No.1, Part II, March 2004 / Donna M. Baudrau - Melville (NY) : American Institute of Physics (AIP), 2004, 1286-1286

Skup
APS March Meeting 2004

Mjesto i datum
Montréal, Kanada, 22.03.2004. - 26.03.2004

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
carbon nanotubes; gas adsorption; specific heat

Sažetak
The low-temperature calorimetric measurements, in the T-range 80 mK to 10 K, can be used as a sensitive technique to investigate the macroscopic NT bundles (~50 mg of material), their vibrational properties [1, 2], but also the adsorption of gases, specifically He^4 [3]. We report here on such studies performed on two kinds of well characterized SWNT bundles prepared either by laser ablation, or by electric arc discharge. They essentially differ in their size, i.e. the mean number of tubes per bundle, which is a determinant parameter for their properties. We have investigated the contribution of He^4 adsorbates in the dilute limit, i.e. in concentration less than a few at. % of C atoms. We could detect very different characteristic regimes for the low-T heat capacity, which exhibits extreme sensitivity to outgassing conditions. For bundles with a few number of NTs the extra contribution to the specific heat due to adsorbed He^4 desplays a typical 1D behavior. This is the first evidence of He atoms localized within linear channels as grooves and interstitials. For larger bundles the corresponding specific heat recovers the 2D behavior akin to the case of He^4 films on planar grafoil substrates. [1] J. C. Lasjaunias et al., Phys. Rev. B 65, 113409 (2002), [2] J. C. Lasjaunias et al., Nanotechnology 14, 998 (2003), [3] J. C. Lasjaunias, K. Biljakovic, J. L. Sauvajol, P. Monceau, Phys. Rev. Lett. 91, 025901 (2003).

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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