Effect of Co2 + content on the magnetic properties of CoxFe3 − xO4/SiO2 nanocomposites
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- Hua, J., Liu, M., Wang, L. et al. Hyperfine Interact (2013) 219: 41. doi:10.1007/s10751-012-0702-8
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Non-stoichiometric CoxFe3 − xO4/SiO2 (x = 0.8, 0.9, 1.0, 1.1) nanocomposites have been prepared by sol-gel method. The structure, morphology and magnetic properties of the obtained samples were characterized by X-ray diffraction, transmission electron microscopy, vibrating sample magnetometer and Mössbauer spectroscopy at room temperature. As the Co2 + content increases, the average particle size of the spherical CoxFe3 − xO4 in the samples decreases and the lattice constants increases. The hyperfine fields for both A- and B-site decrease, while the fraction of Co2 + occupying the A-site increases. Magnetization measurements show the saturation magnetization and coercivity of CoxFe3 − xO4/SiO2 decrease with increasing Co2 + content. The decrease in magnetization results from the weakened A-B interactions between Fe3 + , and the change in coercivity can be related to the variation of Co2 + at B-site and the decreasing particle size.