Influence of nonmagnetic In³⁺ and Sc³⁺ ions co-substitution on the structure, cation distribution and magnetic features of Ni_0.6Cu_0.2Zn_0.2Fe₂O₄ nanoparticles

Ni_0.6Cu_0.2Zn_0.2In_xSc_xFe_2-2xO₄ nanoparticles (NPs) (x ≤ 0.10) were synthesized using the Sol-Gel combustion route to investigate the substitution of non-magnetic Indium (In⁺³) and Scandium (Sc⁺³) ions. XRD (X-ray diffraction) confirmed the purity of all products, exhibiting a single-phase spinel structure. Crystallite size (D_XRD), determined by Rietveld refinement, ranged from 35 to 79 nm. SEM (Scanning electron spectroscopy) and TEM (Transmission electron spectroscopy)/HR-TEM (High resolution transmission electron spectroscopy)were used to analyze morphology. VSM (Vibrating sample magnetometer) measurements at 300 and 10 K revealed narrow hysteresis loops for all samples, confirming their soft ferrimagnetic nature. In³⁺ and Sc³⁺ substitution led to a remarkable alteration in magnetic behavior due to cation redistribution. The saturation magnetization (Mₛ) increased with higher substitution levels (x). Conversely, coercivity (H_c) decreased. The reduction in H_c and squareness ratio (SQR < 0.5) further confirmed the multidomain and soft magnetic character of the nanoparticles. These results demonstrate that the dual In³⁺/Sc³⁺ substitution is an effective method to tune the cation distribution and exchange interactions, which is providing an approach to tailor Ni-Cu-Zn soft magnetic ferrites for innovative applications.