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.
