The effect of yttrium substitution on the magnetic properties of magnetite nanoparticles

Abstract

Superparamagnetic Y-substituted magnetite (YxFe3-xO4,with x = 0.00, 0.10, 0.15, 0.20 and 0.40) nanoparticles were synthesized via hydrothermal reduction route in the presence of citric acid. The synthesized nanoparticles were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), vibrating sample magnetometry (VSM) and gradient field thermomagnetic measurement. The results showed that a minimum amount of citric acid is required to obtain single phase Y-substituted magnetite nanoparticles. Citric acid acts as a modulator and reducing agent in the formation of spinel structure and controls nanoparticle size and crystallinity. Mean crystallite sizes of the single-phase powders were estimated by Williamson- Hall method. Curie temperature measurement of the samples shows that as yttrium content increases, the Curie temperature decreases. Magnetic measurements show that the saturation magnetization of the samples decreases as x increases up to 0.15 and then increases to x = 0.20 and finally decreases again for x = 0.40. © 2014 Elsevier B.V. All rights reserved.