Enhancement of saturation magnetisation through the addition of a nonmagnetic element in substitutional Fe-doped In2O3 powder

•We propose a tuning of room temperature ferromagnetism by co-doping the In2O3-system through nonmagnetic atoms (Mg).•A new doping process was developed to avoid the formation of magnetic nanoparticles.•The analysis revealed that Fe and Mg ions were incorporated into the In3+ sites in the In2O3 lattice without altering the cubic bixbyite structure.•RTFM ordering with remarkable enhancement of the saturation magnetization with decreasing Fe ions and increasing nonmagnetic Mg concentrations was observed.•The enhancement in the magnetic moment with increasing Mg doping is attributed to oxygen vacancies induced by the substitution of Fe and Mg ions into the In3+.