Structural, optical and electrical properties of chemically derived nickel substituted zinc ferrite nanocrystals

•Pure single phase nanocrystalline Zn/Ni ferrites by facile soft chemical route.•Changes in microstructural parameters of Zn ferrite is observed due to Ni inclusion.•Optical band gap shows a maximum while the concentration of Ni increases.•Inverse to spinal ferrite change is observed in ac and dc electrical properties.

Single phase spinel Ni substituted nanocrystalline Zn ferrites have been synthesized using a soft chemical route. Effect of Ni substitution on structure, electrical and optical properties has been investigated. X-ray diffraction study confirms the growth of single phase nanocrystalline Ni substituted Zn ferrites. FTIR and UV–Visible studies delineate the change in structure and optical band gap due to inclusion of Ni ions. Substitution of Ni ion has been manifested on lattice parameter which systematically decreases from 8.448 Å to 8.280 Å. An initial increase followed by subsequent decrease in optical band gap with the increase in Ni content is observed. In addition, both ac and dc electrical studies shows anomalous behavior in conductivity and dielectric properties for the samples having Ni content in the range 0.2–0.6 mol fraction which can be attributed to the normal to inverse spinel structural changes.