Pressure dependence of Raman modes in double wall carbon nanotubes filled with α-Fe.

Jesus Gonzalez (1) , Chrystian Power , Edgar Belandria , Jose Jorge , Fernando Gonzalez-Jimenez , Marius Millot (2) , Sébastien Nanot (2) , Jean-Marc Broto (2) , Emmanuel Flahaut (3)

1 Universidad de Cantabria [Santander]
2 LNCMP - Laboratoire National des Champs Magnétiques Pulsés
3 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

The preparation of highly anisotropic one-dimensional (1D) structures confined into carbon nanotubes (CNTs) in general is a key objective in CNTs research. In this work, the capillary effect was used to fill double wall carbon nanotubes with iron. The samples are characterized by Mössbauer and Raman spectroscopy, transmission electron microscopy, scanning area electron diffraction, and magnetization. In order to investigate their structural stability and compare it with that of single wall carbon nanotubes (SWNTs), elucidating the differences induced by the inner-outer tube interaction, unpolarized Raman spectra of tangential modes of double wall carbon nanotubes (DWNTs) filled with 1D nanocrystallin α-Fe excited with 514 nm were studied at room temperature and elevated pressure. Up to 16 GPa we find a pressure coefficient for the internal tube of 4.3 cm−1 GPa−1 and for the external tube of 5.5 cm−1 GPa−1. In addition, the tangential band of the external and internal tubes broadens and decreases in amplitude. All findings lead to the conclusion that the outer tube acts as a protection shield for the inner tubes (at least up 16 GPa). Structural phase transitions were not observed in this range of pressure.

Mots clés: Carbon nanotubes; Raman scattering; High pressure

Domaines: Matériaux

Jesus Gonzalez, Chrystian Power, Edgar Belandria, Jose Jorge, Fernando Gonzalez-Jimenez, et al.. Pressure dependence of Raman modes in double wall carbon nanotubes filled with α-Fe.. High Pressure Research, 2008, 28 (4), pp.577-582. ⟨10.1080/08957950802485757⟩. ⟨hal-03574634⟩