Study on morphology and magnetic behavior of SmCo5 and SmCo5/Fe nanoparticles synthesized by surfactant-assisted ball milling

A surfactant-assisted ball milling was employed for the processing of SmCo5 and SmCo5/Fe nanopowders in presence of oleic acid as surfactant. Two types of samples: one is the sediment powders slightly larger particle size in the range of 0.2-1 μm and other is the suspension in the milling medium with colloidal particles in the range of 4-20 nm were obtained. Structural and magnetic properties of SmCo5 and SmCo5/Fe sediment powders, as well as their constituent colloidal nanoparticles were investigated by a transmission electron microscopy (TEM), small angle X-ray scattering (SAXS) and vibrating sample magnetometer. TEM analysis on the colloidal particles revealed a plate-like faceted morphology with particle diameter in the range of 4-20 nm, while SAXS analysis suggested that the shape of particles are lamellar with average thicknesses in the range of 0.5-1.0 nm. A possible mechanism for the formation of lamellar particles with faceted morphologies due to the milling process is discussed. Magnetic measurements on these nanoparticles showed superparamagnetic nature, with very low coercivity and remanence values.