Synthesis of stabilized Mn1-xMgxO system (0.001 ≤ x ≤ 0.15) and its structural, thermal, optical and magnetic studies

A novel method of preparation, involving careful formation of a stoichiometric solid solution of stabilized Mn1-xMg x O system for eight different concentrations ofx (0.001 ⩽x ⩽ 0.15) is described. A variety of physicochemical techniques such as X-ray diffraction, DTA-TGA, reflectance spectra, magnetic susceptibility and XPS data are used to determine structure-property correlations in the solid solutions, which are (i) X-ray diffraction studies reveal the linear decrease of cubic lattice parameter with increasing x, (ii) DTA-TG-DTG studies which confirm the formation of solid solution and the stability of these solid solutions in air which increases from 515 to 565 K withx, (iii) the diffused reflectance spectra shows nearly perfect octahedral symmetry around Mn2+ ions, (iv) magnetic susceptibility data indicates the usual dilution effects of diamagnetic ions in antiferromagnetic host lattice, (v) XPS studies reveal the presence of mixed phase of Mn2O3-MgO on the surface which protects the bulk MnO from its further oxidation to higher oxides of manganese. This shows the important role of Mg2+ in the chemical passivation of manganous oxide.