Synthesis and Characterization of CoFe2O4/MWCNTs Nanocomposites and High-Frequency Analysis of Their Dielectric Properties

Abstract

Nanoparticles of CoFe2O4 were synthesized by chemical co-precipitation method. The CoFe2O4/MWCNT nanocomposites were synthesized with increasing contents of MWCNTs, i.e., 0.0, 2.0, 3.0, and 5.0% by weight via ultrasonication method in a dispersive medium using ortho-xylene. The synthesized cobalt ferrite nanoparticles and their nanocomposites were characterized by impedance analyzer, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and x-ray diffraction (XRD) techniques. The XRD indexed patterns confirmed the face-centered cubic structure of CoFe2O4/MWCNT nanocomposites. The average crystallite size in all the samples was in the range of 15 to 35 nm. The decorations of CoFe2O4 on MWCNTs were confirmed by SEM images. The FTIR results showed two vibrational bands. With the increasing contents of multi-walled carbon nanotubes in the cobalt ferrite/MWCNT nanocomposites, the dielectric properties were also enhanced. At 1 MHz, dielectric constant, dielectric loss, and tangent loss factor were increased from 26, 15.1, and 0.580 for pure cobalt ferrite to 47, 28.9, and 0.614 for loading of 5% MWCNTs, respectively. At 1 GHz, dielectric constant, dielectric loss, and tangent loss factor were increased from 11.6, 0.33, and 0.028 for pure cobalt ferrite to 19.4, 0.61, and 0.031 for loading of 5% MWCNTs, respectively. Such a huge increase in the dielectric properties of cobalt ferrite and multi-walled carbon nanocomposites exploited their applications at high frequency.