Synthesis, structure and spectroscopy of Fe2+:MgAl2O4 transparent ceramics and glass-ceramics

We report on a comparative study of transparent Fe:MgAl2O4 (spinel) ceramics and nanophase Fe:MgAl2O4-based glass-ceramics. The 0.1 mol% was synthesized by hot pressing (at 1500 °C/50 MPa) powders obtained the sol-gel method using LiF as sintering aid. ceramic is single-phase material (cubic structure, sp. gr. Fd3‾m, = 8.083 Å) with mean grain size ~50 μm. exhibits broadband transparency 0.2–6.0 μm high in-line transmission at ~1 74.4%. iron ions are presented in single state Fe2+ species tetrahedral (Td) sites. A broad absorption band spanning from ~1.2 to 3.7 assigned 5E → 5T2 (5D) transition Td sites observed, corresponding ground-state cross section 0.28 × 10−18 cm2 1.90 glass-ceramics were prepared secondary two-stage heat-treatments magnesium aluminosilicate glass nucleated titanium oxide doped FeO. Transparent temperature second stage 800–1000 °C multi-phase materials containing two crystalline nanophases, i.e., spinel (mean size: 3.7–7.4 nm) aluminotitanate solid solution 6.4–20.6 nm), well residual silica-rich glass. Glass-ceramics 1050 based Fe-doped sapphirine. For glass-ceramics, has much more complex character it caused interplay different valence states, coordination locations. enter nanocrystals but unlike ceramic, form both VIFe2+ IVFe2+ species. developed promising for saturable absorbers mid-infrared (2–3 μm) lasers.