Magnetic properties of multi-walled carbon nanotube–epoxy composites

Epoxy matrix composites have been prepared using as filler different weight fractions (0.03–1 wt%) of CVD grown multi-walled carbon nanotubes (MWCNTs) containing trapped iron nanoparticles. Magnetic characterization performed at room temperature with magnetic field between −19 and 19 kG shows that the nanocomposites are weakly ferromagnetic at room temperature. An abrupt variation in the dependence of both the coercivity field, BC, and remanent magnetization, MR, with the weight fraction of MWCNTs, ϕ, was found for ϕ=0.4%. Results suggest the formation of MWCNTs agglomerates for increasing weight concentrations, in accordance with SEM micrographs.