METHOD FOR PRODUCING A BORON-CONTAINING SINGLE CRYSTAL OF LITHIUM NIOBATE Russian patent published in 2022 - IPC C30B15/04 C30B29/30 

FIELD: crystals growing.

SUBSTANCE: invention relates to a technology for growing boron-containing single crystals of lithium niobate, close to the stoichiometric composition, by the Czochralski method, in particular to methods for obtaining boron-containing single crystals of lithium niobate, close to the stoichiometric composition. A method for producing a boron-containing lithium niobate single crystal includes preparing a boron-doped charge of lithium niobate of a congruent composition by synthesizing and granulating a mixture of boric acid, niobium pentoxide and lithium carbonate during heating and holding the mixture, melting the charge, crystallizing a single crystal of lithium niobate onto a seed during its rotation and gradual pulling from charge melt, separation of the single crystal from the melt and its holding over the melt, while the synthesis-granulation of a mixture of boric acid, niobium pentoxide and lithium carbonate is carried out at a molar ratio of H₃ВO₃:Nb₂O₅:Li₂CO₃ equal to 1:15.92-853.3:15.05-807.1, heating rate 220-250°C/h to a temperature of 1235-1242°C and holding at this temperature for 5-7 hours, the prepared mixture is melted at a temperature of 1415-1462°C and kept for 5- 8 h, after which the melt temperature is reduced to 1235-1242°C, the crystallization of the lithium niobate single crystal is carried out at a seed rotation speed of 8-12 rpm and a charge pulling speed of 0.7-0.8 mm/h from the melt, and the single crystal is held over the melt within 8-12 hours

EFFECT: invention makes it possible to obtain a boron-containing compositionally homogeneous single crystal of lithium niobate, close in composition to stoichiometric (Li/Nb≈00.99-1.0), having improved optical characteristics and increased resistance to optical damage.

1 cl, 8 dwg, 4 ex