Mesoporous α-Fe2O3 nanospheres: structural evolution and investigation of magnetic properties.

A solvothermal route is adopted to produce mesoporous α-Fe(2)O(3) nanospheres by using polyethylene glycol as soft template and n-butanol/H(2)O as mixed solvent. The mesoporous α-Fe(2)O(3) nanospheres are subjected to calcination at different temperatures, and the specific surface area, pore size, and magnetic properties of the as-prepared nanospheres are investigated. The studies reveal that the pore sizes of the mesoporous α-Fe(2)O(3) nanospheres increase with higher calcination temperature, and high-temperature calcination brings about tightness of the pore wall. Magnetic studies show that aggregation of the small particles raises the Morin transition temperature.