Abstract
The effect of high energy ball milling on the hematite for milling periods of times ranging from 1 to 48 h was investigated by Rietveld analysis based on XRD patterns and Mossbauer spectroscopy. An expansion of the unit cell parameters was observed. Both Scherrer method and Rietveld analysis show an evident decrease of the grain size with the increase of the milling time. Moreover, some dependence of the lattice parameters on the grain size was observed. Mossbauer spectroscopy measurements reveal that there are two kinds of particles which co-exist in the sample: nanostructured and micrometric hematite. The magnetic hyperfine field is affected by the grain size. (C) 2010 Elsevier B.V. All rights reserved.