Hydrothermal Synthesis and Characterization of CoFe2O4 Nanoparticles and Nanorods

This paper presents a low temperature (130 and 160 °C) synthesis route to prepare the spinel phase CoFe2O4 nanoparticles and nanorods. A one-dimensional (1-D) structure of Co-ferrite was successfully synthesized using Cetyl Trimethyl Ammonium Bromide (CTAB) as a surfactant at temperature 160 °C. Structural, electrical, and magnetic measurements have been performed using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and the Vibrating Sample Magnetometer (VSM). XRD patterns show a pure spinel (fcc) structure, showing a complete phase formation at a low temperature of 160 °C, without any subsequent sintering. Average crystallite sizes have been calculated by Sherrer’s and Williamson-Hall methods. As prepared CoFe2O4 nanorods exhibited a uniform shape of diameter 60–80 nm and 600–900 nm in length. The FTIR spectrum for Co-ferrite nanorods shows two intrinsic lattice absorption bands for tetrahedral and octahedral sublattices. DC electrical resistivity of CoFe2O4 nanorods is high up to ∼108 (Ω-cm), as compared to CoFe2O4 nanoparticles (∼107 Ω-cm) at 373 K. Dielectric parameters were measured using a LCR meter, in the frequency range of 1 kHz to 5 MHz. The real and imaginary part of the dielectric constant (ε′ and ε″) and dielectric loss tangent (tanδ) reduces for CoFe2O4 nanorods in comparison to nanoparticles, and has a value of 13.6 and 0.0416, respectively. Magnetic properties were characterized by VSM under a field of 10 kOe and showed that the 1-D structure reduces the magnetization of nanocrystalline CoFe2O4 from 65 emu/gm to 54 emu/gm.