High-quality alpha-Fe nanoparticles synthesized by the electric explosion of wires

The magnetic and structural properties of metallic alpha-Fe magnetic nanoparticles synthesized by electric explosion of wire technique were investigated. As-prepared particles are highly crystalline and present a high saturation magnetization (M-S = 186 +/- 3 emu/g) that is slightly lower than bulk value (M alpha-Fe = 218 emu/g) due to the presence of a very thin non-magnetic FeOx shell, which increases the chemical stability and biocompatibility, making the particles of great interest for a number of applications, including sensing and biomedicine. When the particles are pressed, strong dipole-dipole interactions arise, giving rise to collective ferromagnetic-like behavior observed with magnetic force microscopy, which results in a reduction of the coercivity, thus suggesting that the interparticle interactions can be used as an additional tool to tune the magnetic properties.