METHOD OF GROWING MONOCRYSTALS OF RARE-EARTH-MAGNESIUM PENTABORATES BY SOLUTION-MELT METHOD Russian patent published in 2025 - IPC C30B9/06 C30B29/10 C01B35/12 C01F5/00 C01B17/32 

FIELD: physics.

SUBSTANCE: invention can be used in production of high-power solid-state ultra-compact lasers. Monocrystals of rare-earth-magnesium pentaborates of general formula Yb_0.11Er_0.02R_0.87MgB₅O₁₀, where R = Y, La, Gd, solution is grown by melt method. First, a mixture is prepared containing a crystallisable substance and a solvent, which is potassium trimolybdate K₂Mo₃O₁₀ at ratio RMgB₅O₁₀/K₂Mo₃O₁₀ from 20/80 to 17/83 wt.%. Charge is deposited into a platinum crucible until it is actually filled and placed in a heating furnace containing a spiral fechral heater with thickness of 2.4 mm, winding in the upper and lower parts of which is 105 mm ± 15 mm, and in the central part is 205 mm ± 20 mm. Winding pitch 15 mm ± 5 mm. Then the crucible is gradually heated to 1000 °C at a rate not exceeding 10 °C/h, and held for at least a day for melt homogenisation and monocrystal growth. After that, temperature is lowered to 800 °C at a rate not exceeding 1 °C/h is maintained at this temperature for at least 1 month. After holding, the monocrystal is lifted above the melt to a height of not more than 1 cm and cooled to 300 °C at a rate not exceeding 10 °C/h, then cooled to room temperature. Cooled monocrystal is extracted and freed from melt residues by treatment in concentrated hydrochloric acid.

EFFECT: invention enables to grow large-size monocrystals of rare-earth-magnesium pentaborates free from gas inclusions with controlled content of activator impurities, having physical and chemical stability, high transparency, a wide forbidden zone and a high optical destruction threshold.

1 cl, 3 dwg