Synthesis and investigation of iron-doped manganese aluminate spinel nanopowders and ceramics

The paper reports the results of initial research on the creating of a new laser active element based on manganese aluminate spinel. A technique for preparing iron-doped manganese aluminate spinel is described. Nanopowders with different Al/Mn ratios were obtained by laser ablation followed by vapor condensation in a carrier gas flow. It was found that the particles had an average size of 16.5 nm and a narrow (about 40 nm) size distribution. The compacts prepared from these nanopowders with a diameter of 14 mm and a thickness of 2 mm had a density of 50% of the theoretical one. The compacts were sintered in a vacuum at a temperature of 1300 °C for 3 hours. It is shown that to obtain a singlephase spinel, the molar ratio of Al/Mn cations in the nanopowder should be 1.2–1.75. The transmission spectra of the samples were measured and a transmission range of 2–8 μm and 5 absorption bands were found and the diagram of the lower levels of Fe 2+ was plotted.