Impression of partial replacement of Fe3+ by Sn4+ ion on structural and magnetic features of NiCuZn nanospinel ferrites

In the current study, Ni_0.4Cu_0.2Zn_0.4Fe_2−4xSn_3xO₄ (Sn → NiCuZn) (x ≤ 0.10) nanospinel ferrites (NSFs) have been fabricated by a citrate sol–gel approach, and their structure, morphology, and magnetic features were investigated via XRD, SEM with EDX, HR-TEM, TEM, and VSM, respectively. Their cubic spinel phase was endorsed from their Rietveld refinement. The products’ D_XRD (crystallite sizes) were estimated within the 36–69 nm range. The 10 and 300 K magnetization measurements show ferromagnetic and superparamagnetic behaviors, respectively. The saturation magnetization (M_s) decreases at both temperatures with increasing Sn ratio up to x = 0.06 into the lattice of NSFs but thereafter rises with the additional rise of Sn ratio from 0.06 to 0.10. The alterations of M_s values with Sn substitution have been deliberated via cation redistribution, and changes in the anisotropy constant. H_c value at 10 K almost initially increased for lower Sn content and then decreased at higher Sn content. The coercivity is in reverse proportionality to the particle/crystallite size and domain wall movement of ferromagnetism.