The stability of monodisperse FePt Nanoparticles

Abstract

High coercivity in FePt magnetic nanaoparticles after annealing is the priority of theses systems for application in ultrahigh-density magnetic recording media. Monodisperse FePt nanoparticles were synthesized by superhydride reduction of FeCl 2 .4H 2 O and Pt(acac) 2 at 263 °C under N 2 atmosphere. TEM images show monosized FePt nanoparticles with a diameter of 3.5 nm and a standard deviation of about 10%. The average distance between monodispesre particles is nearly 3nm, which oleic acid and oleylamine surround the FePt nanoparticles as surfactants. Stability of FePt nanoparticles colloidal solution was investigation via spectrophotometer analysis in fabrication and purification stage. The results for FePt nanoparticles dispersed in hexane indicate that by increasing the oleic acid surfactant in centrifugation stage, the concentration and stability of FePt nanoparticles solution increased and by increasing the oleylamine surfactant in fabrication stage, the number and concentration of colloidal nanooarticles increased due to decreasing the size of particles.