Synthesis of Fe$_3$O$_4$ nanoparticles and their magnetic properties

TL;DR

This paper reports the synthesis of Fe₃O₄ magnetic nanoparticles using co-precipitation with surface modifications by sodium citrate and oleic acid, analyzing their structure and magnetic properties.

Contribution

It introduces a method for surface modification of Fe₃O₄ nanoparticles that enhances dispersion and explores the effects on magnetic behavior.

Findings

Surface modification reduces saturation magnetization.

Modified nanoparticles exhibit excellent dispersion.

Surface energy and dipolar interactions are significantly affected.

Abstract

Fe$_3$O$_4$ magnetic nanoparticles (MNPs) were synthesized by a co-precipitation method using sodium citrate and oleic acid as modifiers. Phase composition and microstructure analysis indicate that the sodium citrate and oleic acid have been successfully grafted onto the surface of Fe$_3$O$_4$ MNPs. The magnetic behaviors reveal that the modification can decrease the saturation magnetization of Fe$_3$O$_4$ MNPs due to the surface effect. Fe$_3$O$_4$ MNPs modified by sodiumcitrate and oleic acid show excellent dispersion capability, which should be ascribed to the great reduction of high surface energy and dipolar attraction of the nanoparticles.