Abstract:
In this study, Ni and Zn substituted manganese ferrites, Mn0.85
(Ni, Zn)
0.15
Fe2O4
, 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 welldefined, 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 Mn0.85
Ni0.15
Fe2O4
and 61.4nm for Mn0.85
Zn0.15
Fe2O4
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 Mn0.85
Ni0.15
Fe2O4
and
Mn0.85
Zn0.15
Fe2O4
ferrites, respectively that reveal the formation of the cubic spinel structure.
The Cole-Cole plots for Mn0.85
Ni0.15
Fe2O4
and Mn
0.85
Zn0.15
Fe2O4
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.
