The structure, magnetic properties and cation distribution of Co1-xMgxFe2O4/SiO2 nanocomposites synthesized by sol-gel method

The structure, magnetic properties and cation distribution of Co1-xMgxFe2O4/SiO2 (x=0, 0.2, 0.4, 0.6, 0.8) nanocomposites synthesized by the sol gel method were studied at room temperature by using X-ray diffraction, transmission electron microscopy, vibrating sample magnetometer, and Mossbauer spectroscopy. The lattice constant of Co1-xMgxFe2O4 in the nanocomposite decreased with increasing the Mg2+ content, and average crystallite size was in the range of 33-39 nm. The saturation magnetization of the samples decreased with increasing composition x, while the coercivtiy increased firstly and then decreased, showing a maximum value of 2604 Oe at x=0.6. The Mossbauer spectra were fitted with two Zeeman sextets, indicating that all the samples were completely magnetically ordered. The cation distribution was discussed and the variations of the magnetic moment per formula unit indicated that Co1-xMgxFe2O4 in the nanocomposite was a collinear ferrimagnetic structure. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.