Structural, magnetic, and electrical properties of manganese-substituted magnesium chromate spinel structure

Manganese-substituted magnesium chromate spinel structure with composition Mg1−xMnxCr2O4 (x = 0.0, 0.25, 0.50, 0.75, 1.0) was synthesized by sol–gel auto-combustion route. The polycrystalline powder was characterized using XRD, TGA/DTA, SEM/EDAX, TEM, and FTIR spectroscopy. XRD analysis unveiled the single cubic spinel structure without any additional peak and the lattice constant upsurges with the amount of manganese content were augmented. Thermal analysis reveals the decomposition of organic moieties at different steps and the stability of the spinel structure. Furthermore, SEM measurement shows that grain size lies between 1.74 to 3.17 µm, and EDAX measurement demonstrates stoichiometry according to its composition. TEM also reveals the average particle size around 20 nm. Continuous increase in saturation magnetization and magnetic movement gives information about Mg2+ completely replaced by Mn2+ in A site. At the same time, B site Cr3+ is not interfering with the A site in this particular situation. A persistent decrease in electrical properties and the increase in magnetic movement concerning temperature indicate the replacement of Mg2+ by Mn2+ in A site, while B site Cr3+ is unaffected by Mn2+.