Structural, electric and dielectric properties of Ni0.5Zn0.5FeCoO4 ferrite prepared by sol-gel

• Published in: Journal of magnetism and magnetic materials 2020-04, Vol.499, p.166243, Article 166243
• Main Authors: Omri, Aref, Dhahri, E., Costa, B.F.O., Valente, M.A.
• Format: Article
• Language: English
• Subjects: Ball milling; Cobalt ferrites; Current carriers; Dielectric properties; Diffraction patterns; Ferrites; Mossbauer spectroscopy; Mössbauer spectrometry; Nickel ferrites; Nyquist plots; Raman spectra; Sol-gel processes; Spectrum analysis; Spinel; Temperature dependence; Transport mechanisms; Wavelengths; Zinc
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2019.166243

•The Ni0.5Zn0.5FeCoO4 spinel ferrite is synthesized by a sol-gel technique.•The temperature and frequency dependence of dielectric constants have been investigated.•The electrical properties are found to be strongly dependent on temperature.•The analysis of the thermal variation of the imaginary part of the electrical modulus peak has indicated that the observed relaxation process is thermally activated. Ni0.5Zn0.5FeCoO4 spinel ferrite was elaborated using sol-gel technique. X-ray diffraction patterns indicate that sample has a cubic spinel type structure with Fd-3m space group. The change in Raman modes and relative intensity were observed due to ball milling and consequently to the decrease of particle size and cationic redistribution. The Raman spectra show peaks appearing at 450 and 490 cm−1 corresponding to T2g (2) and T2g (3), respectively. It may be noted that both of these modes shift toward the higher wavenumber with the substitution of Zn by Ni in Ni0.5Zn0.5FeCoO4 ferrite. Mössbauer spectroscopy analysis shows one tetrahedral A-site and two octahedral B-sites. Due to Zn doping, the hyperfine magnetic fields are much smaller than for CoFe2O4 and NiFe2O4 ferrites. The Jonscher’s power low was used to describe the ac-conductivity measurements. Frequency dependence of dielectric constant (ε″) and tangent loss (tan) display a dispersive behavior at low frequencies that can be explained by the Maxwell Wagner model and Koop's theory. Electric modulus formalism has used to study the relaxation dynamics of charge carriers. The complex impedance spectra (Nyquist plots) show well-defined semicircles which are strongly dependent on the temperature.