Impedance spectroscopy and giant permittivity study of ZnFe2O4 spinel ferrite as a function of frequency and temperature

•ZnFe2O4 were prepared by the solid-state reaction.•Large value of the dielectric permittivity.•The dielectric process obeys to three relaxation phenomena.•Our samples have a giant permittivity which can be used in energy storage technology. With good stability in temperature and frequency this material proves to be an interesting candidate to replace the materials traditional dielectrics.