Study of magnetic and dielectric properties of ZnFe2O4/CoCr2O4 nanocomposites produced using sol-gel and hydrothermal processes

•Zinc ferrite and cobalt chromite nanoparticles are synthesized via different routes.•The two compositions are mixed by physical means in different weight ratios.•ZnFe2O4 and CoCr2O4 nanoparticles confirmed the formation of the spinel structure.•Increase in the dielectric constant value was explained by Maxwell–Wagner model.•VSM results reveals the change in behavior of magnetic nature of composite materials.