ИСТИНА

Crystals of yttrium oxo- and pyrosilicate and stillwellite-like lanthanum borosilicate have been obtained from high-temperature solutions. We have studied formation of La-, Nd-, Gd-, Dy-and Ho-phases in borosilicate systems with excess of K2Mo3O10, KF and LiF. La-stillwellite crystallizes in narrow concentration range of initial mixture in the La2O3-SiO2-B2O3-KF-K2Mo3O10 system: from 25-35 wt % LaBSiO5 in solution at 10-20 wt % of KF in solvent. (La,Nd)BSiO5 solid solutions crystallize up to 50 at.% of neodymium in the fluxed melt K2Mo3O10-KF. Increasing Nd concentration leads to formation of a new phase with chemical composition close to Nd3BSi2O10. Replacement of KF with LiF favours a decrease of the melting point and formation of a new borosilicate La3BSi2O10. Gd3BSi2O10 and Dy3BSi2O10 new phases were obtained in the systems ReBSiO5-KF-K2Mo3O10 (Re=Gd, Dy). Y2SiO5:Pr3+ crystals with high concentration of Pr3+ were obtained. Single crystals of NdxY1-xAl3(BO3)4 (x=0.05-0.75), GdxY1-xAl3(BO3)4 (x=0.1-0.75) and NdxGd1-xAl3(BO3)4 (x=0.2), or NYAB, GYAB and NGAB, were grown by both the top-seeded solution growth (TSSG) and spontaneous nucleation using a K2Mo3O10 based flux. Pr, Ho ,Er, Yb, Tm and Lu-doped YAl3(BO3)4 crystals were also grown.