SIZE CONTROLLED SYNTHESIS OF FERROMAGNETIC FERRUS PLATINUM (FePt) NANOPARTICLES BY CHEMICAL REDUCTION

Abstract

Ferromagnetic nanoparticles with uniform size distribution have drawn great attention in the past decades because of their unique magnetic properties and potential applications in high density recording media, exchange-spring permanent magnets and biotechnology. In this thesis, synthesis and characterization of ferromagnetic nanoparticles (FePt) are reported. FePt nanoparticles with different sizes and compositions were successfully synthesized via chemical synthesis in the presence of different surfactants. In organic medium FePt particle size was tuned to a range of from 2 nm to 4 nm. Whereas in Aqueous medium range of FePt particle size as 2nm to 3nm. As-synthesized FePt particles were annealed by making Film of FePt nanoparticle using PEI polymer as surface binding agent by Thermal Annealing treatment in inert environment with various temperatures and time. It was found that FePt nanoparticles can be transferred from disordered A1 phase to ordered L10 phase in several seconds at above 600 ºC. AFM Studies revealed that after annealing there is some particle agglomeration were observed. For the nanoparticles, it was difficult to increase or even maintain the magnetic properties after annealing because of high oxidation affinity of nanoparticles.