SUBSTITUTION EFFECT ON THE STRUCTURE, MORPHOLOGY, ELECTRICAL AND DIELECTRIC PROPERTIES OF Mn0.85 (Ni, Zn)0.15 Fe2O4 FERRITE MATERIALS

Abstract

In this study, Ni and Zn substituted manganese ferrites, Mn0.85(Ni, Zn)0.15Fe2O4, are successfully synthesized by Sol-gel method. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and impedance spectroscopy (IS) characterization techniques are employed to identify the effect of the substitution process on the structure, morphology, chemical composition, electrical and dielectric properties of these ferrite materials. The XRD results confirms that all peaks appeared from both ferrite materials are very sharp and well- defined, which indicates a high crystallinity of both samples. It also reveals the formation of cubic spinel structure with space group Fd3m. The average crystal sizes are found to be 63nm for Mn0.85Ni0.15Fe2O4 and 61.4nm for Mn0.85Zn0.15Fe2O4 ferrites. SEM images confirm that both the prepared samples are almost porous and they have fair uniform closely packed distribution of particles. The EDS analysis reveals that all Mn, Fe, Ni, Zn and O elements are detected in both samples synthesized at 700°C in air for 8hrs. FT-IR study shows, the two strong bands appeared at wavenumbers 582.53 and 591.21cm-1 for Mn0.85Ni0.15Fe2O4 and Mn0.85Zn0.15Fe2O4 ferrites, respectively that reveal the formation of the cubic spinel structure. The Cole-Cole plots for Mn0.85Ni0.15Fe2O4 and Mn0.85Zn0.15Fe2O4 ferrites measured at room temperature in the frequency range from 1Hz to 1MHz show the formation of two successive semicircles from both ferrites. The impedance spectroscopic analysis shows that the values of Z′ for both samples are found to decrease with increase in frequency. It is also found that the dielectric constant decreases continuously with increasing frequency and becomes constant at higher frequency region at room temperature.