FLUX GROWTH AND CHARACTERIZATION OF RARE-EARTH-DOPED NONLINEAR HUNTITE-TYPE BORATE CRYSTALS - Y1-XNDX(AL0.7GA0.3)(3)(BO3)(4) AND Y1-XYBXAL3(BO3)(4)

Single crystals of non-linear Huntite-type berates, with good optical quality, have been grown by slow cooling from fluxes based on the K2O- MoO3 system. Crystals corresponding to the general formula Y1-xNdx(Al0 .7Ga0.03)(3)(BO3)4 (x = 0.05 and 0.15) were obtained with a relatively small size (3 x 3 x 3 mm(3)) whereas those with composition Y1-xYbxAl 3(BO3)(4) (x = 0.005, 0.02, 0.05, 0.10 and 0.15) were, for the first t ime, prepared with a large size (7 x 7 x 5 mm(3)). Differential therma l analysis (DTA) was used to explore the best conditions of growth. Th e dependence of crystals and solvent stability are discussed. Crystal composition was determined by atomic absorption spectrometry and elect ron microprobe analysis, Electron paramagnetic resonance (EPR) spectro scopy was also used to characterize the oxidation state of molybdenum impurities and their localization in the Huntite-type crystal structur e.