Investigation of Magnetic and Dielectric Properties of Cobalt Cubic Spinel Ferrite Nanoparticles Synthesized by CTAB-Assisted Co-precipitation Method

Abstract

In this research work, a novel surfactant (CTAB)-assisted co-precipitation method has been developed for controlled synthesis of CoFe2O4 nanoparticles by using cobalt nitrate, iron nitrate, sodium hydroxide, and CTAB (cetyltrimethylammonium bromide) as reactants. Nanoparticles of CoFe2O4 were synthesized with varying molar amounts of CTAB (0.1M, 0.2M, 0.35M, and 0.4M CTAB). A sample without CTAB (0.0M CTAB) was also synthesized for comparison of properties. Crystal structural, morphological, vibrational spectral, magnetic, and dielectric characterization of synthesized CoFe2O4 nanoparticles were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), and precision impedance analyzer (LCR meter), respectively. XRD results revealed that single-phase pure spinel CoFe2O4 owing to Fd-3m group was synthesized with improved crystallinity for all samples. It was confirmed by SEM analysis that spherical nanoparticles of CoFe2O4 have been synthesized with an average particle size of 25nm. FTIR analysis revealed that absorption peaks observed at 587–583 cm−1and 377–375 cm−1 referred to the tetrahedral complexes and octahedral complexes, respectively. Dielectric properties which were measured between 100Hz and 5MHz using precision impedance analyzer showed that first dielectric constant and dielectric loss decrease rapidly with increase in frequency, and on further increase in frequency, they decrease slowly and become independent of the frequency, which is a characteristic behavior of magnetic spinel ferrites. VSM analysis which was carried out at maximum magnetic field of 8000 Oe at room temperature and pressure showed that all the specimens showed ferrimagnetic behavior with improvement in magnetic properties originating from the use of surfactant in the synthesis procedure.