SYNTHESIS AND CHARACTERIZATION OF Ni0.8Co0.2MnxFe2-xO4 NANO CRYSTALLINE FERRITE MATERIALS

Abstract

Nano sized Nio.8Co0.2MnxFe2-xO4 ferrites with varies compositions (x = 0.05 and 0.1) are successfully synthesized by Sol–gel auto combustion method. The structure, morphology, chemical composition, electrical, dielectric and magnetic properties of these synthesized samples are investigated using x-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS), Fourier transform infrared (FT-IR) spectroscopy, impedance analyzer (IR) as well as Electron spin resonance spectroscopy (ESR). The XRD analysis confirms the phase purity of the synthesized ferrites. It also reveals the formation of spinel structure for both prepared powder ferrites. The lattice parameter and the crystal size of are identified to be 8.538 Å and 58.23 nm, respectively for Ni0.8Co0.2Mn0.05Fe1.95O4 ferrite material; and 8.561 Å and 59.14 nm, respectively for Ni0.8Co0.2Mn0.1Fe1.9O4 ferrite material. The average crystallite size calculated using Debye– Scherer equation also confirms the nano crystalline nature of the samples. EDS patterns confirm the compositional formation of the synthesized samples, i.e., both compounds show the presence of Ni, Co, Mn, Fe and O elements. FT-IR spectra analysis shows the appearance of two strong bands, which are responsible for the formation of cubic spinel structures in both ferrites. From the electrical conductivity study, two different regions, which are frequency independent and dependent regions, are clearly identified. The variation of dielectric properties with frequency shows the polarization behavior of both ferrites. ESR study shows that both ferrite materials possess soft magnetization behavior at room temperature. The magnetization curves of both samples show weak ferromagnetic behavior, with slender hysteresis.