Effect of doping of divalent (Cu2+) and trivalent (Gd3+) metal ions on microstructural and magnetic features of Mn–Zn spinel ferrite nanoparticles

Abstract

Two series of spinel ferrite nanoparticles Mn_0.5Zn_0.5−xCu_xFe_2−yO₄Gd_y (where x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, y = 0, 0.1) synthesized using the co-precipitation method. The techniques of XRD, FTIR, SEM–EDS, TEM-SAED, and VSM were employed to investigate the microstructural, optical, morphological and magnetic properties of the nanoparticles. The XRD findings validated the establishment of a cubic spinel ferrite structure (Fd-3m space group). Crystallite size for Gd³⁺ substituted NPs was in the range of 15–24 nm and for without Gd³⁺ NPs 15–22 nm with varying Copper concentration. The characteristic absorption bands within the range of 400–4000 cm⁻¹ associated with spinel ferrite were detected using the FTIR technique. SEM examination confirmed that the ferrite particle grains are agglomerated. EDS spectra verified the presence of all included components in the composition. Morphology & size analysis was made by TEM-SAED technique where particles shown nearly spherical shape. The measured mean particle size obtained from TEM corresponds with the crystallite size calculated from XRD data. The M–H hysteresis curve was utilized to compute and evaluate the magnetic properties of nanoparticles. The saturation magnetization (M_s), coercivity (H_c), remanence (M_r), and magnetic moment, in connection to structural and microstructural characteristics. Saturation magnetization varied when the concentration of Cu²⁺ increased, from 7.1 to 43.9 emu/g for Gd³⁺ substituted samples and 4.1 to 31.32 emu/g for Gd³⁺ unsubstituted samples. The measured value of H_c is rather low, suggesting that it can be quickly demagnetized and is suitable for electromagnetic applications.