Influence of silicon dioxide medium on the structural and electrical properties of nickel zinc ferrite


Abstract: Nickel zinc ferrite [(Ni$_{0.65}$Zn$_{0.35}$Fe$_{2}$O$_{4}) _{x}$ / (SiO$_{2}) _{1-x}$ where, x = 1.0, 0.85, 0.65, 0.50, 0.35, and 0.15] is synthesized using the glyoxylate precursor method. The synthesis, characterization, and electrical study of nickel zinc ferrites/SiO$_{2}$ powder with low dielectric constant, very low conductivity, and loss tangent with low frequency dispersion, suitable for good insulators, is reported here. X-ray diffraction, TGA, and FT-IR studies are employed for identifying crystalline phases and structure. Crystallite size is calculated by the Scherrer formula and Williamson--Hall equation and found to fall in the range of 4.9--25 nm. TEM of the samples shows spherical particles of uniform size distribution and the spotty rings of SAED patterns are analyzed for identifying the crystal planes. The study confirms a simple and efficient way to synthesize single-phase nickel zinc ferrite (NZFO) spherical particles of nano size ($\approx $15 nm at 1000 $^{\circ}$C) with lower particle agglomeration in comparison to any other methods. Electrical studies are carried out using an LCR meter. The observed value of dielectric constant falls in the range of 10--80, loss tangent in the range of 0.05--0.4, and electrical conductivity in the range of 10$^{-4}$ to 10$^{-7}$ mho m$^{-1}$. These values are respectively functions of temperature, frequency, and the ferrite content in ferrite/SiO$_{2}$ samples. A proper selection of ferrite concentration in the silica medium enables one to prepare NZFO/SiO$_{2}$ material of very low loss tangent with dielectric constant in the range of 10--80.

Keywords: Nickel zinc ferrite, ethylene glycol, tetraethyl orthosilicate, dielectric constant, dielectric conductivity, loss tangent,

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