Showing papers by "A. Loiseau published in 1997"
TL;DR: In this article, it was shown that the growth mechanism for SWNTs must be independent of the details of the technique used to make them, and that the ready availability of large amounts of SWNT can make them much more accessible for further study.
Abstract: Single-walled carbon nanotubes (SWNTs) offer the prospect of both new fundamental science and useful (nano)technological applications1. High yields (70–90%) of SWNTs close-packed in bundles can be produced by laser ablation of carbon targets2. The electric-arc technique used to generate fullerenes and multi-walled nanotubes is cheaper and easier to implement, but previously has led to only low yields of SWNTs3,4. Here we show that this technique can generate large quantities of SWNTs with similar characteristics to those obtained by laser ablation. This suggests that the (still unknown) growth mechanism for SWNTs must be independent of the details of the technique used to make them. The ready availability of large amounts of SWNTs, meanwhile, should make them much more accessible for further study.
2,568 citations
TL;DR: In this article, the first magnetization measurements of individual ferromagnetic nanoparticles (15-30 nm) at very low temperatures (0.1-6 K) were presented.
Abstract: Presented are the first magnetization measurements of individual ferromagnetic nanoparticles (15--30 nm) at very low temperatures (0.1--6 K). The angular dependence of the hysteresis loop evidenced the single domain character of the particles. Waiting time, switching field, and telegraph noise measurements showed for the first time that the magnetization reversal of a well prepared ferromagnetic nanoparticle can be described by thermal activation over a single-energy barrier as originally proposed by N\'eel and Brown. The ``activation volume'' estimated by these measurements was close to the particle volume.
525 citations
TL;DR: In this paper, the soot collected on the anode deposit formed by arcing a hafnium diboride rod with graphite in a nitrogen atmosphere was analyzed with sub-nanometer-scale resolution.
Abstract: Polyhedral and tubular graphitic nanoparticles made of carbon layers and boron nitride (BN) layers have been synthesized. These particles were observed in the soot collected on the anode deposit formed by arcing a hafnium diboride rod with graphite in a nitrogen atmosphere. Elemental profiles with subnanometer-scale resolution revealed a strong phase separation between BN layers and carbon layers along the radial direction. Most of these tubes have a sandwich structure with carbon layers both in the center and at the periphery, separated by a few BN layers. This structure provides insight into the atomistic mechanism of nanotube growth in the boron-carbon-nitrogen ternary system and may lead to the creation of nanostructured electronic devices relying on the controlled production of heteroatomic nanotubes.
441 citations
TL;DR: In this paper, the authors investigated surface induced chemical disorder and step unpairing transition by grazing x-ray diffraction on a vicinal surface of an A 3 B type alloy and found that both transformations occur below and close to the bulk order-disorder transition.
Abstract: Surface induced chemical disorder and step unpairing transition are investigated by grazing x-ray diffraction on a vicinal surface of an ${A}_{3}B$ type alloy $({\mathrm{Cu}}_{83}{\mathrm{Pd}}_{17})$. Both transformations occur below and close to the bulk order-disorder transition. The asymmetry of terraces and the order parameter reflecting chemical order in the surface layer are determined by measuring the shape of crystal truncation rods. Step unpairing and surface disordering are found to be continuous transitions.
10 citations