Investigating the effect of Cd on the structure and magnetic properties of (Mn,Co,Ni,Cu,Zn)Fe₂O₄ high entropy spinel oxide

Evaluating the substitution of Cd for Mn, Co, Ni, Cu, and Zn elements in the high entropy oxide structure (Mn,Co,Ni,Cu,Zn)Fe₂O₄, is the primary focus in this investigation. For this purpose, five different high entropy oxides (HEOs), namely (Cd,Co,Ni,Cu,Zn)Fe₂O₄, (Mn,Cd,Ni,Cu,Zn) Fe₂O₄, (Mn,Co,Cd,Cu,Zn)Fe₂O₄, (Mn,Co,Ni,Cd,Zn)Fe₂O₄, and (Mn,Co,Ni,Cu,Cd)Fe₂O₄ were synthesized using combustion solution synthesis (SCS) method. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), elemental mapping, and field emission scanning electron microscopy (FESEM) were used to analyze the synthesized samples. The analyses confirmed the formation of single-phase (Fd-3m) nanocrystalline powders with an increased lattice parameter. Fourier Transform Infrared Spectroscopy (FTIR) revealed the placement of Cd element in the tetrahedral sub-lattice (A-site). Vibrating sample magnetometer (VSM) was employed to assess the magnetic properties. The results indicated that, in most cases, substitution of Cd for Mn, Co, Ni, Cu, and Zn leads to an increase in both the saturation magnetization (M_s) and coercivity (H_c) of the nanocrystalline powder samples.