Authors: Tahmineh Sodaee Ali Ghasemi Ebrahim Paimozd Andrea Paesano Akimitsu Morisako
Publish Date: 2013/07/11
Volume: 42, Issue: 9, Pages: 2771-2783
Abstract
Cobalt ferrite nanoparticles were synthesized by a reverse micelle process The optimum processing conditions required to fabricate nanocrystalline cobalt ferrite using a reverse micelle technique especially the effect of watertosurfactant molar ratios including w = 8 10 12 and 14 pH values in the range of 8 to 11 and annealing temperatures in the range of 400°C to 800°C were evaluated xRay diffraction XRD fieldemission scanning electron microscopy FESEM vibratingsample magnetometry and superconducting quantum interference device analysis were employed to evaluate the structural and magnetic properties of synthesized nanoparticles XRD analysis confirms that the nanoparticles have a singlephase cubic spinel structure The average particle size increases with increasing pH value and annealing temperature Magnetization study reveals that the cobalt ferrite nanoparticles exhibit a superparamagnetic trend The zerofieldcooled magnetization curves of cobalt ferrite nanoparticles indicated that with an increase in pH value the blocking temperature increases Based on the obtained optimum parameters terbiumsubstituted cobalt ferrite nanoparticles with composition CoFe2−x Tb x O4 x = 01 to 05 were prepared by a reverse micelle process XRD and fieldemission scanning electron microscopy evaluation demonstrated that singlephase spinel ferrites with narrow size distribution were obtained Mössbauer spectroscopy was used to determine the site preference of terbium cation The results confirm that terbium cations were distributed at tetrahedral and octahedral sites but with a preference for the former It was observed that with an increase in terbium content the saturation magnetization increases
Keywords: