Abstract
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 epsilon' and loss tangent tan delta were measured at different frequencies at room temperature. The highest conductivity is achieved for PEG/Ni Fe2O4 and the lowest value of tan delta is obtained for PEG/MnFe2O4 amongst all PEG/MPe(2)O(4) nanocomposites. (C) 2010 Elsevier B.V. All rights reserved.