Synthesis and Magnetic Properties of Cobalt Ferrite (CoFe2O4) Nanoparticles Prepared by Wet Chemical Route

TL;DR

This study reports the synthesis of cobalt ferrite nanoparticles via a wet chemical method, analyzing how size and annealing conditions affect their magnetic properties, including coercivity and magnetic moments.

Contribution

It introduces a wet chemical synthesis route for cobalt ferrite nanoparticles and investigates the relationship between particle size, annealing conditions, and magnetic properties.

Findings

Nanoparticles range from 15-48nm depending on annealing.

Coercivity peaks at around 28nm particle size.

Large coercivity of 10.5kOe observed at 77K.

Abstract

Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single phase cobalt ferrite nanoparticles in the range 15-48nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at around 28nm. A very large coercivity (10.5kOe) is observed on cooling down to 77K while typical blocking effects are observed below about 260K. The high field moment is observed to be small for smaller particles and approaches the bulk value for large particles.