Effects of Milling Conditions on Nano-scale MnFe(P,Si) Particles by Surfactant-assisted High-energy Ball Milling

The influence of the milling conditions on the nano-scale MnFe(P,Si) particles obtained by surfactant-assisted high-energy ball milling has been investigated by X-ray diffraction (XRD) and magnetic measurements. The presence of surfactant oleic acid prevents the re-welding of crushed particles and enhances the dispersion of nanoparticles in the solvent during the ball milling. The XRD peak intensities decrease and the peaks broaden with increasing milling time, indicating a decrease in grain size. For increasing milling time, the spontaneous magnetization becomes lower and the thermal hysteresis becomes smaller. The surfactant concentration does not have a strong impact on the magnetic properties of the obtained nanoparticles, which is consistent with the X-ray diffraction data showing the same patterns at different surfactant concentrations.