Microstructure of (Na0.5La0.5)MoO4 crystals coactivated with cerium and erbium ions

Crystals with the scheelite structure have been grown by the Czochralski technique from a melt of composition (Na0.5La0.345Ce0.15Er0.005) MoO4 (NLM: Ce, Er) and have been characterized by scanning and transmission electron microscopy and x-ray microanalysis. The crystals are shown to contain carbon inclusions and CeO2 precipitates, the latter oriented relative to the host matrix: [100]{0 (1) over bar2} NLM: Ce, Er || [ 100]{0 (1) over bar1} CeO2. High-temperature annealing leads to recrystallization and growth of the CeO2 particles, which seems to be responsible for the adverse effect of annealing on the optical quality of the crystals.