Synthesis of Fe2O3 nanoparticles by new Sol-Gel method and their structural and magnetic characterizations

TL;DR

This study presents a modified sol-gel synthesis method for Fe2O3 nanoparticles, analyzing how size, phase composition, and annealing temperature influence their structural and magnetic properties.

Contribution

It introduces a new sol-gel synthesis approach for Fe2O3 nanoparticles and systematically investigates size and phase control parameters affecting their magnetic behavior.

Findings

Particle size decreases with higher annealing temperature and citric acid concentration.

Magnetization and coercivity increase with annealing temperature.

Surface effects significantly influence magnetic properties at smaller sizes.

Abstract

Fe2O3 nanoparticles of different sizes ranging from 22 to 56nm were synthesized chemically by a modified sol-gel method. Pure alpha phase particles as well as particles with admixture of alpha and gamma phase were obtained and identified by x-ray and M\"ossbauer measurements. Different size and phase controlling parameters have been identified. The average size of the particles decreases with increased annealing temperature of the gel and decreases with the increase in the concentrations of the (citric acid). The annealing temperature affects the relative fractions of the two phases and consequently the magnetization of the particles. The magnetization of the particles (Ms) and coercivity (Hc) increase consistently with the increase in the annealing temperature. For the same relative amount of the two phases, the coercivity (Hc) and the moment of the particles increase with the decrease in the size of the particles, indicating the role of surface effects in the magnetic behaviour.