Investigation of magnetic properties of Al substituted nickel ferrite nanopowders, synthesized by the sol-gel method

► Al substituted Ni ferrite (NiFe2−xAlxO4) nanoparticles were prepared by sol-gel route. ► Tcs of the nanoparticles are higher than those related to their bulk counterparts. ► By the substitution of Al for Fe, the Curie temperatures are decreased. ► Magnetization with respect to Al content shows a minimum of x=1.0.