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For the first time, rare earth doped strontium hexaferrite nanoparticles Sr(1−x)LaxGdySmzFe(12−(z+y))O19 (x = 0.3, y = z = 0.01) were synthesized by the sol–gel combustion method in this paper. A single-phase with space group P63/mmc was confirmed by X-ray diffraction (XRD) and the average crystallite size was found to be 46 nm. The existence of absorption bands of the hexaferrite phase structure was shown by the Fourier transform infrared (FT-IR) spectra. Raman analysis confirms the formation of all crystallographic hexaferrite sites. The effect of the rare earth elements on the nanoparticles' morphology was evaluated by scanning electron microscopy (SEM) analysis. Energy-dispersive X-ray spectroscopy (EDX) results confirm the sample homogeneity. The value of the band gap was found to be 1.52 eV from the UV-vis NIR spectra. The magnetic analysis of the prepared sample revealed at room temperature a coercivity, saturation magnetization, remanence ratio, maximum magnetic energy product, switching field distribution, and a Curie temperature of 4296.39 Oe, 62.29 emu g−1, 0.49, 7.79 KJ m−3, 0.663, and 490 °C, respectively. These results suggest that this material has a significant function in industry, which could be beneficial for recording media applications. Using first-principles calculations, the site preference of the doping elements Sm, Gd, and La, as well as the effect of doping with these elements on the structural, magnetic, and electronic properties of the M-type strontium hexaferrite, was investigated. [ABSTRACT FROM AUTHOR]

For the first time, the nanoparticles of LiCo2O4 spinel were elaborated at low temperature by a new process using non-standard Moroccan metallurgical grade reagents. Thermogravimetric analysis (TGA) of the as prepared powders was carried out for the determination of decomposition temperature. X-ray diffraction (XRD) patterns confirmed the formation of LiCo2O4 at 400 °C, which has a cubic spinel structure with the space group (Fd3m). The crystallite size and lattice parameters were found to be 19 nm and 8.153 Å, respectively, which illustrate the transition of the spinel to the nanocomposite HT-LiCoO2–Co3O4–CoO at 900 °C. The FTIR (Fourier Transform Infrared) spectra showed three fundamental absorption bands (v1, v2 and v3), which are attributed to the stretching vibrations of octahedral and tetrahedral sites, respectively. Particle size, morphology and chemical composition of spinel LiCo2O4 are evaluated using transmission electron microscopy (TEM) coupled with EDS. The EDS spectrum has confirmed the purity of the compound by the presence of Co and O. In addition, first-principles calculations were performed on the spinel material using the Full-Potential Linear Augmented Plane Wave method. The corresponding electronic structure is studied and the Li average voltage is calculated using the GGA+U method with the present work self-consistently calculated Ueff values. [ABSTRACT FROM AUTHOR]