Effect of rare earth (Nd3+) metal doping on structural, morphological, optical and magnetic traits of Zn–Mg nano-ferrites

Abstract

Herein, we report the synthesis of Zn0.7Mg0.3NdxFe2–xO4 (where, x = 0.0, 0.01, 0.02) ferrite nanoparticles by employing the sol–gel auto-combustion technique. The X-ray diffraction (XRD) pattern suggests the formation of a pure cubic structure, without any impurity phase, with an Fd3m space group at room temperature. With increasing doping amount, the crystallite size is reported as 35–41 nm, while the lattice parameters rise from 0.8381 to 0.8395 nm. Field emission scanning electron microscopy (FESEM) images show the formation of spherical grains with agglomerated morphology in all the samples, with grain sizes ranging from 49 to 103 nm. Energy dispersive X-ray spectroscopy (EDX) and elemental mapping investigation confirm the chemical purity of all the samples. Fourier transform infrared (FTIR) analysis shows the presence of two prominent peaks around 440 and 560 cm−1 that correspond to the octahedral and tetrahedral positions. In addition, the existence of five Raman active vibrational modes in all produced specimens again confirms the structural purity of all the samples. The M−H curve shows that saturation magnetization (Ms) first increases from 14.98 to 28.22 emu/g and then decreases to 18.98 emu/g with increasing doping amount. This is due to the A-B type super-exchange interaction for the synthesized samples. The variation in coercivity (Hc) and magnetic anisotropy (K1) suggest the thermal stability of all the samples and can be utilized in transformers and solenoids.