The effect of temperature on the structural, dielectric and magnetic properties of cobalt ferrites synthesized via hydrothermal method

Abstract

Abstract A series of cobalt ferrite nanoparticles were prepared using hydrothermal process by varying the reaction temperature. The structural, magnetic and dielectric properties have been studied with the help of X-ray diffractometer (XRD), vibrating sample magnetometer (VSM) and impedance analyzer respectively. XRD spectra of all samples confirmed the formation of cobalt ferrite (CoFe2O4) nanoparticles (NPs). The lattice constant ‘a’ for temperature series samples is averaged around 8.4023 Å. Crystallite size of temperature series is calculated by Debye–Scherer formula that lies in the range of 15.04–20.49 nm. Its values increase because the chance of coalescence increases by increasing temperature. The maximum packing factor is obtained for the sample with highest reaction temperature. From VSM data, we get the M–H hysteresis curves for complete temperature series which confirms the magnetic nature. The maximum saturation magnetization 150.67 emu/g is obtained for the sample prepared at highest temperature. Different magnetic parameter such as saturation magnetization, coercivity, retentivity, squareness ratio, anisotropy constant and magneton number has been calculated from VSM data. AC response of all prepared ferrites was studied with impedance analyzer of frequency range 20 Hz to 20 MHz. Ferrites are the insulating materials, so, eddy current does not induce in transformer cores made of ferrite materials. In the medical field cobalt ferrite is used for drug delivery, as a biosensor and in MRI.