Spectroscopic analysis of "MgAlON" spinel powders: influence of nitrogen content

The thermoluminescence (TL) and fluorescence spectra of magnesium aluminium oxynitride "MgAlON" and magnesium aluminate MgAl2O4 spinel powders have been analysed. Two broad peaks at about 100 and 300 °C appear in the TL spectra of MgAl2O4 and seem to be related to electron and hole release from [AlMg√] and [MgAl′] traps, respectively. The intensity of each peak strongly depends on the nature of the annealing atmosphere (neutral, oxidizing or reducing). TL spectral analyses have shown the presence of two intense emissions at 520 and 690 nm attributed to the Mn2+ and Cr3+ emitting centers, respectively. A study on MgAl2O4 is used as a reference for MgAlON powders, which can be considered as a solid solution derived from magnesium aluminate. Disturbance in the emission spectrum of Cr3+ is clearly observed with the nitrogen/oxygen substitution.