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The exploration of aluminum (Al3+) ion substituted nickel–zinc–cobalt (Ni–Zn–Co) nanoferrites is still at the infancy stage, although the structural, electrical, and magnetic properties have been widely investigated. Single-phase cubic nanospinel ferrites of Ni0.4Zn0.35Co0.25Fe2–x Al x O4 (0 ≤ x ≤ 0.12) with space group Fd 3m were confirmed by the Rietveld refinement X-ray diffraction (XRD) data. Lattice constants displayed a declining trend with compositions x. The average particle size was found to range from 29 to 25 nm. Selected area electron diffraction (SAED) patterns were indexed according to space group Fd 3 m , indicating that nanoparticles are well crystallized. Samples’ modes of vibrations swung between redshift and blueshifts as detected in the Raman spectra. The saturation magnetizations (M s) were in the range of 59.85–86.39 emu/g. Frequency-dependent dielectric constants (ε′) and ac resistivity (ρ) measurement suggested that samples were highly resistive. These resistive nanoferrites with high saturation magnetizations may function effectively for multifaceted electronic devices.

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This study explored the structural, morphological, optical, and magnetic properties of Ni0.4Zn0.35Co0.25Fe2−x Al x O4 (0 ≤ x ≤ 0.12) nano-spinel ferrites. Nanocrystalline cubic structure formation and weight loss percentage were determined by thermogravimetric analysis and differential scanning calorimetry (TGA - DSC). Single-phase cubic spinel structures with Fd3m space group of synthesized samples were confirmed by Rietveld refinement X-ray diffraction (XRD) data. The particle sizes were found to be in the range of 6.7 nm–5.25 nm, and agglomeration occurs inside the ferrite samples. The atomic planes and strong crystallinity were detected through SAED images. The characteristic peaks of the Raman spectra identified the bonding between the cations and anions in the sub-lattices. The optical bandgaps (E g ) were found to be in the range of 2.1 eV–2.52 eV. S-shape hysteresis (M-H) loops identified the superparamagnetic nature of the nano-samples. The studies’ outcomes indicated the applicability for biomedical applications of these nano samples.

Strong gravitational field induces sedimentation of atoms due to the different body forces acting on respective atoms, and gives a tool for controlling elemental compositions in condensed matter. Vanadium oxide (V-O system) has large contrast in phases like VO, V2O3, VO2, V2O5 etc., and shows the respective interesting diverse electrical and optical properties. We performed a strong-gravity experiment (0.397106G at 400°C for 24 hours) on a V2O5 polycrystal using the high temperature ultracentrifuge to examine the composition change and further the structure change. It was found by the XRD and Raman scattering method that VO2 and V2O3 phases appeared and the amounts were increased, while one of the V2O5 phase decreased gradually along with the increasing gravitational field.