Palatnikov Mikhail, Sidorov Nikolay, Kadetova Alexandra, Titov Roman, Biryukova Irina, Makarova Olga, Manukovskaya Diana, Teplyakova Natalya, Efremov Ilja
Tananaev Institute of Chemistry-Subdivision of the Federal Research Centre «Kola Science Centre of the Russian Academy of Sciences», 184209 Apatity City, Russia.
Materials (Basel). 2023 Jan 11;16(2):732. doi: 10.3390/ma16020732.
Physical and chemical properties have been studied in lithium niobate (LiNbO, LN) crystals grown by Czochralski from a boron doped melt. Optical uniformity and optical damage resistance of LiNbO:B crystals have been compared with control crystals of nominally pure congruent (CLN) and near-stoichiometric (NSLN KO) composition. LiNbO:B crystals structure has been studied. Studied LiNbO:B crystals have been grown from differently synthesized charges. The charges have been synthesized from a mixture NbO:B-LiCO using homogeneously doped NbO:B precursor (sample 1, (B) = 0.0034 wt% in the charge) and by a direct solid phase synthesis from NbO-LiCO-HBO mixture (sample 2, (B) = 0.0079 wt% in the charge). Only traces of boron (10-10 wt%) have been detected in the samples. We have established that concentration of anti-site defects Nb is lower in both LiNbO:B than in CLN crystals. XRD analysis has confirmed that B cations localize in faces of tetrahedral voids O of LN structure. The voids act as buffers at the anion sublattice distortion. Sample 1 has been shown to have a structure closer to NSLN KO crystal than sample 2. We have also shown that the chemical purity of LN crystal increases compared to the melt purity because boron creates strong compounds with impurities in the melt system LiO-NbO-BO. Metals impurities thus stay in the melt and do not transfer to the crystal.
已对通过提拉法从掺硼熔体中生长的铌酸锂（LiNbO₃，LN）晶体的物理和化学性质进行了研究。将掺硼的LiNbO₃晶体的光学均匀性和抗光损伤性能与标称纯同成分（CLN）和近化学计量比（NSLN KO）组成的对照晶体进行了比较。对掺硼的LiNbO₃晶体结构进行了研究。所研究的掺硼LiNbO₃晶体是从不同合成的原料中生长出来的。这些原料是由Nb₂O₅:B-Li₂CO₃混合物合成的，使用了均匀掺杂的Nb₂O₅:B前驱体（样品1，原料中硼含量（B）=0.0034 wt%），以及由Nb₂O₅-Li₂CO₃-H₃BO₃混合物直接进行固相合成（样品2，原料中硼含量（B）=0.0079 wt%）。在样品中仅检测到痕量硼（10⁻¹⁰ wt%）。我们已经确定，两种掺硼LiNbO₃晶体中反位缺陷Nb的浓度均低于CLN晶体。X射线衍射分析证实，B阳离子位于LN结构中四面体空位O的面中。这些空位在阴离子亚晶格畸变时起到缓冲作用。已表明样品1的结构比样品2更接近NSLN KO晶体。我们还表明，与熔体纯度相比，LN晶体的化学纯度有所提高，因为硼与熔体体系Li₂O-Nb₂O₅-B₂O₃中的杂质形成了强化合物。金属杂质因此留在熔体中，不会转移到晶体中。
