Customized magnetic properties of (Mn_0.5Zn_0.5)[Eu_xNd_xFe_2-2x]O₄ nanospinel ferrites synthesized via ultrasonic irradiation approach

The demand of the multifunctional nanospinel ferrites (NSFs) is ever-increasing for various advanced applications wherein the fundamental knowledge of the magnetic features became essential. In this view, high purity NSFs of composition (Mn_0.5Zn_0.5)[Eu_xNd_xFe_2-2x]O₄ (0.00 ≤ x ≤ 0.05) were synthesized via the ultrasonic irradiation. The influence of the co-substituents (Eu³⁺/Nd³⁺) concentration on the microstructures, morphologies and magnetic behaviors of these as-prepared NSFs were evaluated. The samples were characterized thoroughly using diverse analytical instruments. The X-ray powder diffraction patterns of these NSFs verified their phase purity. The SEM and TEM analyses revealed the existence of spherical shaped grains with size around 20 nm. The produced NSFs showed a superparamagnetic (SPM) behavior at room temperature and ferromagnetic (FM) behavior at very low temperatures. Both saturation and remanent magnetization values of the studied NSFs were improved at lower Eu³⁺/Nd³⁺ contents up to x = 0.02 and then dropped beyond x > 0.02. It was shown that the magnetic traits of these NSFs can be tailored by controlling the Eu³⁺/Nd³⁺ concentrations.