Chemically induced order disorder transition in magnesium aluminium spinel

Magnesium aluminate spinel (MgAl2O4) spinel powder was synthesized by nitrate citrate auto-ignition route taking different ratios of nitrate and citrate solution. The 'as prepared' black ash was calcined at different temperatures in the range 650-1250 °C for 9 h. Phase evolution of calcined powder samples as studied by X-ray diffraction indicates the presence of disorder at lower calcination temperatures, which transforms to an ordered structure at higher calcination temperatures. Finally, Raman spectroscopy confirms the order-disorder phase transition in spinel sample.