%0 Journal Article
%T Infrared and Raman Spectroscopic Study of Carbon-Cobalt Composites
%A Andr¨¦ Tembre
%A Jacques H¨¦nocque
%A Martial Clin
%J International Journal of Spectroscopy
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/186471
%X Analysis of carbon-cobalt thin films using infrared spectroscopy has shown existence of carbon-cobalt stretching mode and great porosity. The Raman spectroscopy and high-resolution transmission electron microscopy have been used in order to investigate the microstructure of the films. These films exhibit complex Raman spectra suggesting the presence of amorphous and crystallized phases. The different fractions of phases and the correlation between the atomic bond structures and the Raman features depend on the cobalt content. 1. Introduction In the last years, nanocrystalline magnetic materials made of metallic nanoclusters dispersed in an amorphous matrix have attracted considerable interest owing to their magnetic properties and promising applications as memory units for high-density storage and fundamental research [1, 2]. Hayashi et al. [3] have reported the fabrication and characterization of magnetic thin films of h.c.p cobalt nanocrystals of around 8 nm size encapsulated in graphite-like carbon cages. Due to their ferromagnetic nature, the cobalt grains have great potential for ultra-high-density magnetic recording media. The incorporation in the carbon network of various metallic atoms, like Ti, Zr, Ta, Cr, Mo, W, Fe, Co, and Ni, is a good alternative to improve the tribological [4¨C7], electric [8¨C10], and magnetic [11¨C15] properties of carbon films for various applications as solid lubricant films, microelectrodes, or magnetic films. It has been reported that insertion of metallic atoms in amorphous carbon matrix changes the fraction of Csp3-coordinated carbon sites [16] Various techniques have been used to fabricate metallic nanoclusters dispersed in an amorphous matrix; we can mention filtered cathodic vacuum arc [17, 18], pulsed laser deposition [19], cosputtering [10, 20], and dual beam evaporation system [5]. Among these different methods, cathodic arc deposition is widely used [21, 22]; this technique is characterized by high degree of ionization and great ion kinetic energy and deposition rate. Cathodic arc processes produce unwanted macroparticles in the mm range which are removed from the plasma by a magnetic filter; on the contrary, anodic arc do not suffer from macroparticles contamination, which was the main motivation of using this deposition technique in the present study. Recently, it has been reported that incorporation of iodine in amorphous carbon [23, 24] and boron in diamond [25] leads to a metal-insulator transition at low temperature. Cobalt-doped carbon thin films at 0.3% cobalt content, deposited by a pulsed anodic
%U http://www.hindawi.com/journals/ijs/2011/186471/