structural, morphological, optical and dielectric examination of magnesium chromite (MgCr₂O₄) spinel oxide

The citrate–nitrate method was employed to synthesize the magnesium chromite (MgCr₂O₄) spinel, followed by calcination at 700℃ for 3hours. The synthesized compound was analyzed using techniques including powder XRD, SEM-EDAX, FTIR, UV-DRS and LCR Meter. The structural analysis was carried out using X-ray diffraction, which revealed the formation of the cubic crystal symmetry of the sample with the corresponding Fd-3 m space group. The average particle size of the sample was calculated around 13.26nm. Further, the diffraction pattern was refined by Fullprof Software which validated the single phase cubic structure formation. Using tetrahedral and octahedral positions, the lattice vibrations of the associated chemical bonds were identified using Fourier transform infrared (FTIR) spectroscopy. SEM (Scanning electron microscopy) micrographs showed the spherical nature of the particles and the constituent particles were between 10 and 40 nm in size. The optical bandgap value was evaluated using the Tauc’s plot. Pellets of the powdered sample were prepared for determining the dielectric aspects including dielectric constant (ε’), tangent loss (tanδ and ac conductivity (σ_ac) in the frequency range of 100Hz–4MHz, at room temperature. The charge transport mechanism was explored from the complex impedance spectroscopy study. The obtained results indicate that magnesium chromite may be a potential candidate in the fabrication of sensors, micro-electronic devices, and other electronic equipment.