Comment on ‘Order–disorder phase transition induced by swift ions in MgAl2O4 and ZnAl2O4 spinels’ by D. Simeone et al., J. Nucl. Mater. 300 (2002) 151–160

In this letter, structure factor calculations and computer simulated powder X-ray diffraction patterns are used to challenge conclusions reached in a recent study by D. Simeone et al. regarding radiation-induced phase transformations in MgAl2O4 spinel. Based on experimental results presented by D. Simeone et al. and previously by other researchers, and based on the structure factor results presented here, spinel most likely succumbs to a phase transformation under irradiation that involves a profound change in the arrangement of cations in the lattice. The space group is modified by the transformation and the new, metastable structure is most likely a defective rocksalt structure. These conclusions are at odds with the description of the spinel metastable phase offered by Simeone et al.