LAUSR

Abstract Solid-phase synthesis of optical ceramics MgAl2O4 with various concentrations of iron as an impurity element was carried out without using sintering additives. Ceramics were characterized by intense absorption in the UV spectral region due to both intrinsic F-type defects and intrinsic iron ions. The effect of nonradiative energy transfer from optically active centers of the F-type to the impurity Fe3+ ion was observed. In ceramic samples with an iron concentration more than 0.4 mol%, the decrease in the intensity of the Fe3+ luminescent signal (coordination number, Z = 6) is due to the effect of concentration quenching, as well as the conversion of Fe3+ → Fe2+ ions. It was shown that, as a result of high-temperature synthesis, optically active centers of Fe3+ and Fe2+ are formed, which are localized in regular (octahedral and tetrahedral) lattice sites and defect anti-sites. According to the data of optical absorption spectroscopy, as the content of iron ions increases, the concentration of Fe2+ (Z = 6) increases. A new luminescence band with a maximum at 2.3 eV was detected by photoluminescence spectroscopy, presumably associated with the luminescence of Fe3+ in tetrahedral lattice sites (Z = 4).