Magnetic and electrical properties of carbon nanotube/epoxy composites

Composites based on epoxy resin filled with carbon nanotubes (obtained on metal catalysts: cobalt, iron and bimetallic iron - cobalt) were prepared. The influence of carbon nanotubes on the electrical conductivity and magnetic properties of the obtained composites was examined. Magnetic resonance spectra of the studied samples were dominated by a single, intense, broad and asymmetrical line, which is typical for ferromagnetic resonance (FMR) spectra of strongly interacting iron and cobalt nanoparticles forming agglomerates. The FMR spectra of the modified carbon nanotubes in epoxy were satisfactory fitted by using two components of the Lorentzian lineshape. Magnetization processes had a strong influence on all parameters of FMR spectra. The surface anisotropy is assumed to be the most important contribution to the overall magnetic anisotropy. Electric properties of all composites were improved and composite containing carbon nanotubes obtained on iron cobalt catalyst exhibited the highest value of electrical conductivity.