Structural and Magnetic Consequences of Mn_0.6Zn_0.4Fe_2−xGd_xO₄ Ferrite

Gadolinium-substituted spinel ferrite nanopowders Mn_0.6Zn_0.4Fe_2−xGd_xO₄ (x = 0, 0.1, 0.2, 0.3, 0.4) were prepared by sol-gel auto-combustion method and post subsequent heat treatment. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared (FTIR), and vibrating sample magnetometer (VSM) methods were used in order to investigate the effect of Gd ³⁺ cation substitution on structural and magnetic properties of Mn–Zn ferrite. The results of XRD measurements and FTIR spectra showed the formation of single spinel ferrite for x ≤ 0.2 that is associated with some secondary phases at higher amounts of Gd ³⁺ doping. The lattice parameter was found to increase with increasing Gd content. The average particle size of substituted Mn–Zn ferrite became smaller by addition of gadolinium. The room temperature saturation magnetization values increased up to 56.4 emu/g for x = 0.1, and then decreased upon further Gd substitution. Similar behavior was observed in the coercivity changes. The observed magnetic properties were explained on the basis of net magnetic moment changes and structural characterization upon Gd substitution in the compound.