METHOD OF GROWING DOPED CRYSTALS OF LITHIUM NIOBATE WITH COMPOSITION CLOSE STOICHIOMETRIC, AND DEVICE TO THIS END

摘要

FIELD: metallurgy.;SUBSTANCE: invention relates to the technology of growing monocrystals using Chokhralsky method. Growth of doped crystals of lithium niobate with composition close to stoichiometric is done on an inoculating crystal from molten mixture of lithium niobate of identical composition with ratio Li/Nb equal to 0.938-0.946 and containing 9-13 mol % K₂O and 0.5-2.5 mol % MgO or ZnO, in conditions of applied electric field with current density of 0.2-40 A/m². A device is provided for realising the method, comprising a housing with a growth station and a cooling chamber, crucible 1, placed in the growth station, induction heater, top metallic heating shield 4, fitted above the crucible 1, mechanism for moving the crystal with a coupling rod, a rod with a holder 3 for the inoculating crystal 2. The device is also provided with a regulated direct current source 10 with electrodes; under the inoculating crystal 2 there is an additional load from electrically conducting material, separated from the wall of the holder by electrically insulating material. One of the electrodes is connected to the crucible 1, and the second - to the load.;EFFECT: invention allows for growing large optically homogenous crystals of lithium niobate with composition close to stoichiometric Li/Nb0,994, additionally doped with MgO or ZnO, composition of which in the top and bottom parts of the crystal is virtually the same, without destroying the inoculating crystal.;5 cl, 2 ex, 2 dwg