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.