Abstract
Functionalized multiwall carbon nanotubes (MWCNT-COOH) were decorated with crystalline cobalt ferrite nanoparticles (CoFe2O4 NPs) by co-precipitation reaction to form MWCNT-COOH/CoFe2O4 hybrid. The hybrid was characterized by X-ray diffraction analysis, transmission electron microscopy (TEM), Fourier transfom infrared spectroscopy and vibrating sample magnetometry. The results confirmed that MWCNTs and CoFe2O4 NPs coexisted in the hybrid. The TEM results showed a thick layer of CoFe2O4 was intimately connected to the surface of MWCNTs. The saturation magnetization value of the hybrid was 11.5 emu/g. There has been a high frequency fluctuation in conductivity, however, above all dc conductivity changes and resulting activation energy is calculated from the Arrhenius plots. It is found to vary with the temperature regions. This can be attributed to the existence of a conventional temperature independent tunneling conduction mechanism, which can be also explained that the metallic conduction is a dominant mechanism around room temperature. The ac conductivity of MWCNT-COOH/CoFe2O4 hybrid might also be a consequence of the predictions of the universal dynamic response and the 'n' power exponents could be determined with lower concentration of the addition in the hybrids. (C) 2013 Elsevier B.V. All rights reserved.