Synthesis and Investigation of Magnesium–Aluminum Nanopowders and Ceramics Activated by Copper

Nanopowders of two crystalline phases, magnesium–aluminum spinel (98 wt %), and cuprite (2 wt %) have been obtained by laser evaporation of a solid target, which is a mechanical mixture of simple oxides (MgO, Al2O3, CuO). These nanopowders have been used to prepare test samples of transparent Cu:MgAl2O4 ceramics, the IR transmission spectra of which revealed two new strong absorption bands at λ1 ≈ 1.55 (1.45) μm and λ2 ≈ 3.45 (3.03) μm, corresponding to transitions between the Stark levels 2E( $${\text{t}}_{2}^{6}$$ e3) and 2T2 ( $${\text{t}}_{2}^{5}$$ e4) of Cu2+ ions in octahedral and tetrahedral positions, respectively.