Improvement of LiNbO3 Microstructure by Crystal Growth with Potassium

Malovichko, G.; Грачев, В. Г.; Yurchenko, Lesya P.; Proshko, V. Ya.; Kokanyan, Edvard; Gabrielyan, V. T.

doi:10.1002/pssa.2211330124

Cited by 104 publications

(45 citation statements)

References 2 publications

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“…% K 2 O. As was shown by Malovichko et al, 23,24 these crystals are nearly potassium free and their composition is close to stoichiometric. To obtain pure stoichiometric crystals, Kitamura et al 13 also used an alkali additive, i.e., Li by applying the continuous filling double crucible method, thereby again preparing bulk crystals in the Li 2 O-Nb 2 O 5 binary system from extremely Li-rich melt (58% Li 2 O) similarly to the early attempts of Peterson 1 and Carruthers et al 2 Later, by using starting melts with K 2 O added in concentrations from 10 to 16 mol.…”

Section: Growth Of Stoichiometric Linbo 3 a Early Worksupporting

confidence: 60%

“…The first experiments on growing sLN with K 2 O additive used congruent Li/Nb ratios in the starting melt. 23 Later, by testing various flux compositions, Polg ar et al 28 found that the crystals grown from fluxes with starting composition of Li/Nb ¼ 1 and K 2 O in the range of 0. 16-0.195 During crystallization of the hLNi phase, the point representing the liquid in equilibrium with the solid moves on the liquidus surface towards one of the monovariant lines, limiting the liquidus surface.…”

Section: Growth Of Stoichiometric Linbo 3 a Early Workmentioning

confidence: 99%

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Growth, defect structure, and THz application of stoichiometric lithium niobate

Lengyel

Péter

Kovács

et al. 2015

Applied Physics Reviews

105

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Owing to the extraordinary richness of its physical properties, congruent lithium niobate has attracted multidecade-long interest both for fundamental science and applications. The combination of ferro-, pyro-, and piezoelectric properties with large electro-optic, acousto-optic, and photoelastic coefficients as well as the strong photorefractive and photovoltaic effects offers a great potential for applications in modern optics. To provide powerful optical components in high energy laser applications, tailoring of key material parameters, especially stoichiometry, is required. This paper reviews the state of the art of growing large stoichiometric LiNbO 3 (sLN) crystals, in particular, the defect engineering of pure and doped sLN with emphasis on optical damage resistant (ODR) dopants (e.g., Mg, Zn, In, Sc, Hf, Zr, Sn). The discussion is focused on crystals grown by the high temperature top seeded solution growth (HTTSSG) technique using alkali oxide fluxing agents. Based on high-temperature phase equilibria studies of the Li 2 O-Nb 2 O 5 -X 2 O ternary systems (X ¼ Na, K, Rb, Cs), the impact of alkali homologue additives on the stoichiometry of the lithium niobate phase will be analyzed, together with a summary of the ultraviolet, infrared, and far-infrared absorption spectroscopic methods developed to characterize the composition of the crystals. It will be shown that using HTTSSG from K 2 O containing flux, crystals closest to the stoichiometric composition can be grown characterized by a UV-edge position of at about 302 nm and a single narrow hydroxyl band in the IR with a linewidth of less than 3 cm À1 at 300 K. The threshold concentrations for ODR dopants depend on crystal stoichiometry and the valence of the dopants; Raman spectra, hydroxyl vibration spectra, and Z-scan measurements prove to be useful to distinguish crystals below and above the photorefractive threshold. Crystals just above the threshold are preferred for most nonlinear optical applications apart holography and have the additional advantage to minimize the absorption even in the far-infrared (THz) range. The review also provides a discussion on the progress made in the characterization of non-stoichiometry related intrinsic and extrinsic defect structures in doped LN crystals, with emphasis on ODR-ion-doped and/or closely stoichiometric systems, based on both spectroscopic measurements and theoretical modelling, including the results of first principles quantum mechanical calculations on hydroxyl defects. It will also be shown that new perspective applications, e.g., the generation of high energy THz pulses with energies on the tens-of-mJ scale, are feasible with ODR-doped sLN crystals if optimal conditions, including the contact grating technique, are applied. V C 2015 AIP Publishing LLC.

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Section: Growth Of Stoichiometric Linbo 3 a Early Worksupporting

confidence: 60%

Section: Growth Of Stoichiometric Linbo 3 a Early Workmentioning

confidence: 99%

Growth, defect structure, and THz application of stoichiometric lithium niobate

Lengyel

Péter

Kovács

et al. 2015

Applied Physics Reviews

105

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“…Three basic procedures are used for obtaining stoichiometric LN crystals with x C ≈ 50%: post-growth vapor transport equilibrium (VTE) treatment of congruent samples in Li-rich powder [15,16], double crucible growth [17,18], and growth from melts with the addition of potassium [19][20][21][22][23]. Undoped stoichiometric samples have regularly ordered ideal lattices with R3c group symmetry at temperatures below ferroelectric phase transition at 1500 K (Fig.…”

Section: +mentioning

confidence: 99%

Electron paramagnetic resonance and electron‐nuclear double resonance of nonequivalent Yb³⁺ centers in stoichiometric lithium niobate

Malovichko

Bratus

Грачев

et al. 2008

Physica Status Solidi (b)

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Lithium niobate crystals doped with ytterbium were studied using Electron Paramagnetic Resonance (EPR) and Electron Nuclear Double Resonance (ENDOR). The tremendous narrowing of EPR lines in nearly stoichiometric samples, when compared to those in congruent samples, allowed us to distinguish nine non‐equivalent centers, as well as line splitting caused by the hyperfine interaction of ytterbium electrons with the nuclear spins of two magnetic isotopes, 171Yb and 173Yb. Eight of the nine centers are described for the first time. It was found that three of the centers have axial C3 symmetry, and all others have the lowest C1 symmetry due to the presence of intrinsic defects and/or charge compensation defects in the near neighborhood of Yb3+. Characteristics of the g ‐tensor for all of the centers and hyperfine tensors for axial centers were determined. The ENDOR observations of Nb nuclei in the nearest neighborhood of Yb13+ gave direct evidence that the dominated axial Yb1 center has no charge compensator in its nearest surroundings (distant charge compensation mechanism). Both the EPR and ENDOR data for the main axial ytterbium center are explained by a supposition that Yb3+ ions substitute for Li+. Possible models for low‐symmetry centers are discussed. The obtained numerous spectroscopic parameters can be used as cornerstones for model calculations of Yb3+ centers in lithium niobate. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…The general relative defects quantity (n) of Mg doped LN crystal relatively to the stoichiometric one can be defined as [17]:…”

Section: Deficiency Evaluation Of Mg-doped Ln Crystalsmentioning

confidence: 99%

NMR Analysis of Mg Ion Localization in LiNbO₃Crystal

et al. 2010

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The analysis of cation sublattices population in magnesium doped LiNbO 3 crystals is carried out. It is shown that volume concentration of lithium vacancies (V Li ) monotonously increases with increasing of MgO content in the crystal up to the threshold value. A series of LiNbO 3 crystals with various concentration of Mg 2+ were investigated by 7 Li and 93 Nb Nuclear Magnetic Resonance (NMR). It is concluded that the peculiarities of NMR spectra in Mg-doped LiNbO 3 crystals can be explained by the formation of defect complexes including Mg Li ions and V Li on the shortest distances between them.

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Improvement of LiNbO3 Microstructure by Crystal Growth with Potassium

Cited by 104 publications

References 2 publications

Growth, defect structure, and THz application of stoichiometric lithium niobate

Growth, defect structure, and THz application of stoichiometric lithium niobate

Electron paramagnetic resonance and electron‐nuclear double resonance of nonequivalent Yb³⁺ centers in stoichiometric lithium niobate

NMR Analysis of Mg Ion Localization in LiNbO₃Crystal

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Improvement of LiNbO3 Microstructure by Crystal Growth with Potassium

Cited by 104 publications

References 2 publications

Growth, defect structure, and THz application of stoichiometric lithium niobate

Growth, defect structure, and THz application of stoichiometric lithium niobate

Electron paramagnetic resonance and electron‐nuclear double resonance of nonequivalent Yb3+ centers in stoichiometric lithium niobate

NMR Analysis of Mg Ion Localization in LiNbO3Crystal

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Electron paramagnetic resonance and electron‐nuclear double resonance of nonequivalent Yb³⁺ centers in stoichiometric lithium niobate

NMR Analysis of Mg Ion Localization in LiNbO₃Crystal