A study of ZnFe2O4 nanoparticles modified by ferric nitrate

► The structure of surface modified ZnFe2O4 nanoparticles by Fe(NO3)3 is studied using TEM, EDX, XPS, XRD and VSM. ► This modified particles have a ZnFe2O4 core, an external γ-Fe2O3 shell and an other mixed Fe(NO3)3·9H2O and ZnO layer. ► The magnetization of the modified particles is related to the concentration of Fe(NO3)3solution in a non-monotonic fashion. ► Below a concentration 0.5 M, the magnetization of the modified particle enhanced with increasing the concentration.