Authors: V. Kislov, Yu. Gulyaev, B. Medvedev, I. Taranov, V. Kolesov, V. Kashin, S. Gubin, G. Khomutov, E. Soldatov, M. Artemiev and S. Gurevich
Affilation: Russian Academy of Sciences, Russian Federation
Pages: 192 - 195
Keywords: carbon nanotoroids, nanodiscs, magnetic clusters nanowires, helices
This work is a result of a coherent effort of a consortium of Russian research groups in Nanotechnology (INTC - Interdisciplinary Nanotechnology Consortium) aimed at creating molecular electronic devices based on individual and collective properties of specially designed and fabricated nanoclusters. Recently we have discovered and reported organized self-assembling superstructures of magnetic metal nanoparticles, including nanowires, helices and nanotubes and also predicted a number of new topologically closed possibilities. Intensive experimental search for such topologically closed objects led to the discovery of carbon and carbon-metal nanotoroids. Initial observation of toroids (by AFM, STM, and HRTEM methods) was made for pure carbon, but gradual increase of metal to some optimal concentration dramatically increased the yield of toroidal structures. Size of superstructures is ~ 10 nm for carbon and ~ 30 nm for carbon-metal (outer diameter), with inner diameter ~1/3 of the total. The possibility of such structures was discussed earlier, but we also discovered carbon-metal nanocapsules with shapes like nanodiscs. Incorporation of metal atoms into carbon seems to soften mechanical properties of superstructures with some optimal ratio for producing complex topologies at atmospheric pressure. Changing concentrations and metal (Mo, Cr, etc.) leads to differences in shapes and size of superstructures.