Abstract:
Nanoparticles of MFe2O4(M=Co, Co0.5Mg0.5, Co0.5Ni0.5, Co0.5Zn0.5) and MFe2O4 (M=Co, Co0.5Mg0.5, Co0.5Ni0.5, Co0.5Zn0.5)/MWCNTs nanocomposites with weight percentage varying from 0.0%, 2.0%, 3.0%, 5.0% were synthesized by chemical co-precipitation method and novel ultrasonication method respectively. Impedance Analyzer, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) techniques were used for the characterization of the synthesized nanoparticles and their respective nanocomposites. The face centered cubic structure of the spinal phase were confirmed by the XRD pattern. The average crystallite size remained within the range of 24 ± 7.8 nm in all the synthesized samples. The decorations of MFe2O4 (M=Co, Co0.5Mg0.5, Co0.5Ni0.5, Co0.5Zn0.5) on multi walled carbon nanotubes confirmed by scanning electron microscope images. Two stretching vibrational bands were observed in the spectra of Fourier Transform Infrared Spectroscopy (FTIR). The dielectric properties were observed to be enhancing with enhancing quantity of multi walled carbon nanotubes. The Cole-Cole plots of ac impedance show that the resistance was only due to the contribution by grain boundary. At 1 MHz, dielectric constant, dielectric and tangent losses were increased from 38, 23.1, 0.532 for pure cobalt ferrite to 82.330, 48.7, 0.651; 8.253, 2.519, 0.298 for pure cobalt magnesium ferrite to 26.026, 8.909, 0.570; 7.13, 5.03, 0.361 for pure cobalt nickel ferrite to 16.887, 11.293, 0.587 and 45, 15.1, 0.787 for pure cobalt zinc ferrite to 26.7, 15.1, 0.958 for loading of 5% MWCNTs respectively. Such huge enhance in the dielectric properties exploited its applications at high frequency
