LAUSR

Abstract The present work is focused on the effect of substitution of Co2+ and Cu2+ ions on the structural, morphological, magnetic and optical properties of nanocrystalline ternary doped ferrite nanoparticles (NPs) having formula Mn0.4Co0.6-xCuxFe2O4 (x = 0, 0.2, 0.4, 0.6). They were synthesized using sol-gel precursor methodology and then sintered at 300 °C for 3 h and characterized by XRD, FT-IR, 57Fe Mossbauer and magnetometry. Alteration in surface morphology and surface area was studied using SEM-EDX, TEM and BET analyses. XRD patterns confirmed the formation of single phase ferrite NPs. Doping of Cu2+ ions in MnFe2O4 NPs led to slight increase in magnetization, whereas doping with Co2+ ions appreciably increased the magnetization. The results were correlated to magnetic moment of cations. Maximum saturation magnetization value was 65.0 emu/g for ternary ferrite NPs having formula Mn0.4Co0.4Cu0.2Fe2O4. Doping of MnFe2O4 with Co2+ and Cu2+ ions enhanced surface area. The change in Mossbauer parameters suggested the alteration in environment of Fe3+ ions in presence of different divalent ions. Optical studies revealed lowering in band gap up to 2.03 eV on doping and minimum band gap was observed in Mn0.4Co0.4Cu0.2Fe2O4 NPs. The results confirmed the improved magnetic and optical properties of ternary doped ferrite NPs as compared to pristine counterparts.