Authors: MAJID FARAHMANDJOU
Abstract: A comparison of the synthesis and structural properties of magnetic FePt nanostructures is presented. The FePt nanoparticle system is an excellent candidate for ultrahigh-density magnetic recording. Monodisperse FePt nanoparticles were synthesized by the superhydride method. The composition of nanocrystals was determined by energy dispersive spectroscopy (EDS). Transmission electron microscopy (TEM) images showed monosized FePt nanoparticles with a diameter of 3.5 nm. The average distance between the monodisperse particles was nearly 2 nm. In order to determine the stability of nanoparticle colloidal solution, a measure of stability was defined via spectrophotometric analysis. The magnetic measurement showed that as-made FePt was first superparamagnetic at room temperature; after annealing at 600 °C for 4 h, the nanoparticles gained the ability to phase transition to L1_0-FePt, and the coercivity of the nanocrystals was raised to 6.5 kOe.
Keywords: L1_0 phase, FePt nanoparticles, superparamagnetism, coercivity, nanocrystals
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