Morphological, structural, surface, thermal, chemical, and magnetic properties of Al-doped nanostructured copper ferrites

Aluminum-doped copper ferrite nanoparticles synthesized via thermal decomposition were analyzed for Al³⁺ substitution effects. Nanocrystalline doped copper ferrite with a crystallite size <9 nm was characterized using several advanced techniques, including X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The degree of thermal decomposition used for doping copper ferrite at the nanoparticle level correlates well with the quantitative, dimensional, and structural characterizations. The Scherrer equation and Williamson–Hall method were employed to determine the general lattice strain and constants. Structural properties, such as the oxygen positional parameters, radii of the octahedral and tetrahedral sites, hopping lengths, bond lengths and angles, site bonds, and edge lengths, were determined using XRD patterns. The improved A–B super-exchange interaction was demonstrated by the discrepancy in the theoretically anticipated bond angles. The analysis of magnetic hysteresis (M − H) using a vibrating sample magnetometer (VSM) and XPS confirmed the improvement in the super-exchange interaction. XPS results suggest that Fe and Cu in the crystal lattice are in the form of Fe^III and Cu^II, respectively. The investigation of the degree of inversion, state, and composition using XPS aids to understand the properties of the nanostructured copper ferrites. The saturation and remnant magnetization were determined from hysteresis loops at 1.8 T obtained using the VSM at room temperature. The noncollinear spin and efficient sublattice interactions are responsible for the decrease in M_s and M_r.