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A key challenge in the fabrication of ferromagnetically filled carbon-nanotube buckypapers in the presence of Cl-radicals is the achievement of a preferential horizontal nanotube-alignment. We show that a horizontal-alignment can be achieved by tuning two main CVD parameters for a fixed dichlorobenzene concentration: the precursor-evaporation temperature and the flow rate. [ABSTRACT FROM AUTHOR]

The recent identification of superconductive effects in multilayer graphene systems exhibiting coexistence of rhombohedral and Bernal structural phases has attracted great attention. Complex effects have been reported in the presence of dislocations and/or solitons between graphene layers. Local magnetic fields and percolative effects have also been identified in the presence of wrinkling and disclinations. Interestingly, a recent report has also demonstrated the local stabilization of disorder-rich rhombohedral phases in low dimensional systems comprising of multiwalled carbon nanotubes modified with sulfur. In this work we identify a variation in the predicted ABA Bernal graphitic ordering of multiwalled carbon nanotubes (CNTs) fabricated in the presence of dichlorobenzene as a growth-promoter. The presented results highlight the stabilization of a high density of dislocations in samples produced by pyrolysis of low concentrations of ferrocene. We present an in-depth investigation of the dislocation-rich interfaces, especially by employing HRTEM analyses, evidencing a spontaneous local-insertion of low-dimensional atomic-lines (or solitons) into neighbouring atomic layers of curved graphene. Furthermore, by employing a methodology involving highly controllable cooling-rates and subsequential characterization through X-ray diffraction (XRD), we demonstrate a rapid migration of interstitial carbon, with relaxation of Fe3C into α-Fe and stabilization of local body centred tetragonal phases within the body centred cubic lattice of the nanowires. [ABSTRACT FROM AUTHOR]

Boundary layer chemical vapour synthesis is a fabrication approach which exploits random fluctuations within the viscous boundary layer established between a laminar flow of pyrolyzed ferrocene and a rough substrate, to yield iron filled radial carbon nanotubes (CNTs). The key feature of this method is the significant enhancement of the encapsulated nanowire-length, which has been explained in terms of the diffusion gradient established at the open-tip of growing CNTs. In this work, we carried out a statistical investigation on the possible relationship between the width of the inner-CNT-cavity and the nanowire diameter within radially grown iron filled CNTs. A systematic analysis of nanowire-continuity allowed for the identification of particularly high filling rates, with nanowire-lengths up to 20 μm and an almost complete filling of the CNT-capillary. Two types of contact-modes could be identified between the catalyst particles and the CNTs: the first type, in which the catalyst-diameter is comparable with the width of the inner CNT-cavity (full catalyst encapsulation), and the second type, in which the base particle is found to be not fully encapsulated (i.e. only partially encapsulated within the inner CNT-cavity). The observed CNT/catalyst-base interactions resemble those reported in recent studies for tangential and intermediate-tangential growth-modes occurring after nanotube-cap nucleation. Comparative statistical analyses performed on other types of Fe-filled CNT films (flower-like structures and buckypaper) obtained by pyrolysis of ferrocene or ferrocene/dichlorobenzene mixtures are further discussed. [ABSTRACT FROM AUTHOR]