Nanostructured CuO-α-Fe2O3 solid solution obtained by high-energy ball milling

The mixture of alpha-Fe2O3 and CuO crystalline powders in equimolar ratio was subjected to high-energy ball milling to investigate the solid solution process in this system. The phase evolution in the system during the milling was studied by means of X-ray diffraction and Mossbauer spectroscopy. It was found that nanostructured solid solution of CuO-alpha-Fe2O3 with a corundum structure was obtained. Within the solid solution, there existed a gradient distribution of concentration of CuO from the surface to the interior of alpha-Fe2O3. The dissolution of CuO in the alpha-Fe2O3 greatly lowered the Neel temperature of alpha-Fe2O3, which resulted in paramagnetism of the as-milled solid solution whose Mossbauer spectrum showed a doublet absorption line at room temperature. (C) 2004 Elsevier B.V. All rights reserved.