Bi-modal improvement of the physico-chemical characteristics of PEG and MFe2O4 subnanoferrite

MFe2O4 (M = Mn2+, Ni2+, Co2+ and Cu2+) ferrite powders were prepared by flash auto-combustion reaction. The structural identification of the samples was carried out using X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and IR spectra. The study established the formation of sub-nanosized particles especially for MFe2O4 (M = Ni, Co and Cu) ferrites. MFe2O4/PEG (polyethylene glycol) composites were prepared by cold uniaxial pressing. The magnetic properties were studied by carrying out the hysteresis of MFe2O4 and PEG/MFe2O4 composite at room temperature. The data showed that MnFe2O4 has the highest saturation magnetization while CoFe2O4 has the largest coercive field due to the high anisotropy of Co2+ ions. The ac electrical conductivity as well as the dielectric constant ε′ and loss tangent tan δ were measured at different frequencies at room temperature. The highest conductivity is achieved for PEG/Ni Fe2O4 and the lowest value of tan δ is obtained for PEG/MnFe2O4 amongst all PEG/MFe2O4 nanocomposites. © 2010 Elsevier B.V. All rights reserved.