Effect of La³⁺ doping concentration on the structural, electrical, dielectric, and magnetic properties of -Fe₂O₃ nanoparticles

Lanthanum (La)-substituted alpha-Fe2O3 (pure, 2%, 5%, 8%, and 10%) nanopowder with altering concentration was fabricated using the sol-gel technique. The effect of trivalent La3+ ions on the microstructural, electrical, dielectric, and magnetic properties of the hematite nanopowder was investigated. X-ray diffraction (XRD) pattern of pure and La-doped samples was indexed as a rhombohedral phase with the R3cR3c space group of hematite having crystallite size ranging from 13.5 to 33.4 nm. The existence of La3+ ions in the alpha-Fe2O3 matrix was confirmed by the EDS spectra. Furthermore, XRD findings are in-line with FTIR observation. The resistivity plots demonstrated two different regions corresponding to two dissimilar kinds of conduction mechanisms. Investigation of resistivity data indicates the variable-range hopping and nearest-neighbor hopping conduction mechanisms are present in the 100-300 K and 300-400 K temperature slots, respectively. The dielectric analysis of undoped & La-substituted alpha-Fe2O3 was carried out in the temperature range 100-400 K and followed the variation in lattice parameters and morphology of samples. Magnetic study reveals that magnetic properties were significantly modified with the addition of La(3+)ions in the hematite lattice.