The effect of particle size on the characteristics of FeCo nanoparticles

Some size-dependent characteristics of FeCo nanoparticles are investigated in this paper. The nanoparticles are fabricated using a coprecipitation route and their sizes are controlled by changing the reaction time. Transverse electron microscopy (TEM) images show that the nanoparticles are all spherical with an average size of 2-6 nm. The average size obtained from X-ray diffraction (XRD) measurements is in the range 1-3 nm. Magnetic measurements reveal that the nanoparticles are ordered ferromagnetically and have a high coercivity of about 500 Oe. In our measurements, the coercivity was decreased with decreasing particle size, indicating that the nanoparticles were in a single-domain region. Production of FeCo nanoparticles with high coercivity and fine dimension is highly promising for future recording media technology. (C) 2010 Elsevier Ltd. All rights reserved.