Dielectric and Magnetic Properties of Pure and Doped Cobalt Ferrite Nanoparticles

Abstract

The exceptionally unique magnetic and electric properties of ferrites have always been of strong interest leading to their extensive commercial use. Cobalt ferrite is one of the materials being used in microwave, electronic and magnetic devices. In present research study Nickel, Zinc, Magnesium and Manganese substitution is performed in a series of Co0.5(Ni, Zn, Mg, Mn)0.5 Fe2O4.Synthesis was performed using sol gel method and aqueous solutions of nitrates were used to prepare pure and doped Cobalt Ferrite nanoparticles. Calcination of the prepared samples was performed at 950 oC for 3 hours. The samples were characterized using X-ray Diffraction (XRD), Scanning electron microscopy and Fourier transform Infrared spectroscopy. Impedance analyser was used to analyse the dielectric properties. Magnetic properties of the samples were studied using Vibrating Sample Magnetometer. XRD analysis confirms the Spinel crystal structure of prepared. Crystallite size was calculated using Debye Scherer formula and it came out in the range of 26 nm- 38nm. Vibrating band positions were studied using FTIR. Dielectric studies revealed high value at low frequency while decreases with increasing frequency in dielectric constant. Similarly, the dielectric loss value was high for low frequency while small for high frequency. While value of tangent loss decreases with increasing frequency. The AC conductivity is maximum at higher frequency which represents the dominance of hoping conductivity over band conductivity. While Ac impedance shows decreasing trend in Ac impedance with increasing frequency. While for Electric Modulus it is shown that in low frequency region the M‟ value is very low (approaching to zero) while with increasing frequency its value increases and approaches to maximum asymptotic value for all samples. VSM shows increase in saturation magnetization for cobalt nickel ferrite while it decreases for other samples. For pure Cobalt ferrite, the Mr= 19.34emu/g. while its value increases for Cobalt Nickel ferrite and Cobalt Zinc ferrite (43.32 emu/g, 24.34 emu/g). While decreases for Cobalt magnesium ferrite and Cobalt Manganese ferrite (17.9 emu/g, 17.34 emu/g) . The Coercivity value increases for the dopants as compare to pure cobalt ferrite