Abstract

In this paper, FePt nanocrystals have been prepared by adding LiBEt3H to the phenyl ether solution of FeCl₂. 4H₂O and Pt(acac)₂ precursors in the presence of oleic acid and oleylamine surfactants and 1,2-hexadecanediol as the reducing reagent at 195°C, followed by refluxing at 245°C by sol process. Similarly, Pt nanoparticles were made by adding 1, 2-hexadecanediol as the reducing reagent to the phenyl ether solution of Pt (acac) ₂. The results of Transmission electron microscopy (TEM) images showed that 2 to 7 nm Pt nanoparticles are formed via one step growth  whereas, bimetallic 4 nm magnetic FePt nanocryctals are formed by two step growth as core-shell with good uniformity in size and shape. The size measurement results indicated that the standard deviation of FePt nanoparticles improves to 8% because of two step growth process. In order to phase transition from fcc to L1₀ structure_, the FePt nanoparticles were annealed at 750°C for 4 h. The structural properties of FePt nanoparticles were analyzed by XRD spectra. To prevent FePt nanoparticles from sintering, NaCl particles were used as the separating media. SEM and TEM observations of FePt show the salt-matrix FePt nanoparticles with size of 40 nm after annealing.

Key words: Growth, iron-platinum (FePt) nanoparticles, equilibrium interactions, sol process.