Structure and magnetic properties of hydrothermally synthesized CuFe2O4 and CuFe2O4/rGO composites

•Cu-substituted Nickel ferrites CuxNi1-xFe2O4, with (0.0 ≤ x ≤ 1.0), were synthesized by sol–gel auto combustion method.•Samples have high homogeneity, high crystallinity, small crystallite size, and perfect stoichiometry.•Fine nanoparticles with a crystallite size of 25 nm to 35 nm were obtained.•The saturation magnetization and magnetic moment per formula unit values increase with nickel ion content increases.