Effect of chromium substitution on the dielectric properties of mixed Ni-Zn ferrite prepared by WOWS sol–gel technique

• Cr doped mixed Ni-Zn ferrites were successfully synthesized by a newly developed WOWS sol gel technique.
• The specific surface area and specific surface area to volume ratio increased with decrease in particle size.
• The resonance peaks appeared in dielectric loss graphs, shifting towards low frequency with the increase in Cr concentration.
• The prepared samples have the lowest values of the dielectric constant.
• The dielectric constant were observed to be inversely proportional to square root of the AC resistivity.

Cr+3 doped Ni-Zn nanoferrite samples with composition Ni0.5Zn0.5Fe2-xCrxO4(x = 0.1, 0.2, 0.3, 0.4) were synthesized With Out Water and Surfactant (WOWS) sol-gel technique. The structural, morphological and dielectric properties of the samples were investigated. The lattice constant, crystallite size, theoretical density and porosity of each sample were obtained from X-ray diffraction (XRD) data. The specific surface area and specific surface area to volume ratio increased with the decrease in the size of Cr+3 doped Ni-Zn ferrite nanoparticles, as the concentration of Cr+3 increased. The SEM analysis revealed that the particles were of nano size and of spherical shape. The dielectric parameters such as dielectric constant (ε′) and dielectric loss (tanδ) of all the samples as a function of frequency at room temperature were measured. The AC conductivity (σAC) was determined from the dielectric parameters, which showed increasing trend with the rise in frequency.

Variation of AC conductivity (σAC) as a function of natural log of angular frequency (lnω) for Ni0.5Zn0.5Fe2-xCrxO4 nanoferrites at room temperature.Figure optionsDownload as PowerPoint slide