Dielectric, impedance and modulus spectroscopic studies of Co0.3Cd0.7Zn1.5xFe2−xO4 nanoparticles

Abstract

Spinel ferrites have caught the attraction of researchers in the modern world. In this work, the spinel ferrites having formula Co0.3Cd0.7Zn1.5xFe2−xO4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared by Microemulsion method. Through XRD analysis, it was confirmed that all the samples were spinel ferrites. Crystallite size was found in the range of 9–17 nm, which was later on confirmed by SEM and EDX. Lattice parameter showed increasing trend which was due to larger ionic radii of Zn2+ as compared to Fe3+. Impedance analyzer disclosed the electrical properties of prepared samples. Real and imaginary part of dielectric constant, impedance and modulus was determined with applied frequency range from 1 MHz to 3 GHz. The detailed electrical investigations were investigated in the frequency range of 100–3 GHz. Real and imaginary parts of impedance Z′ and Z″ in the above frequency and substitution case suggested the existence of one relaxation regime which corresponds to grains which was totally different from its counterpart of bulks and has strong correlation with other ferrites. Real and imaginary part electrical modulus M′ and M″ further showed the grains effect with increasing zinc substitution under the suppression of electrode polarization. A non-Debye relaxation behavior and the frequency-dependent conductivity were observed in dielectric spectra, which was also consistent with the results of AC conductivity spectra. Dielectric constant and dielectric loss showed a decreasing trend with increasing frequency and same was that with tangent loss. AC conductivity increased with increasing the frequency. Cole–Cole graph was plotted between M′ and M″ which confirmed the effect of only grains. Excellent dielectric properties suggest that these prepared nanoparticles are good for high-frequency device applications.