Solid state NMR study supporting the lithium vacancy defect model in congruent lithium niobate

Blümel, Janet; Born, E.; Metzger, T. H.

doi:10.1016/0022-3697(94)90057-4

Cited by 71 publications

(52 citation statements)

References 21 publications

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“…time of flight neutron diffraction measurements, 158 and later NMR results. 159 To describe recent Raman spectroscopic results, a mixed model containing both lithium and niobium vacancies was also introduced. 160 Our spectroscopic results shown in Section III favour the Li vacancy model which is commonly accepted as also emphasized in Ref.…”

Section: A Intrinsic Defectsmentioning

confidence: 99%

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

Lengyel

Péter

Kovács

et al. 2015

Applied Physics Reviews

103

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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: A Intrinsic Defectsmentioning

confidence: 99%

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

Lengyel

Péter

Kovács

et al. 2015

Applied Physics Reviews

103

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“…Mg, [121,122] 27 Al, [123,124] 49 Ti, [125, 126] 65 Cu [127] and 91 Zr. [128,129] As evidenced from the data presented in Figure 12 a and b, the total suite of four-and six-coordinate niobates shows no tendency to correlate (linearly or otherwise) with j y j and j a j , respectively, as both data sets describe a random scatter.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

A ⁹³Nb Solid‐State NMR and Density Functional Theory Study of Four‐ and Six‐Coordinate Niobate Systems

Hanna¹,

Pike²,

Charpentier³

et al. 2010

Chemistry A European J

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A variable B(0) field static (broadline) NMR study of a large suite of niobate materials has enabled the elucidation of high-precision measurement of (93)Nb NMR interaction parameters such as the isotropic chemical shift (delta(iso)), quadrupole coupling constant and asymmetry parameter (C(Q) and eta(Q)), chemical shift span/anisotropy and skew/asymmetry (Omega/Deltadelta and kappa/eta(delta)) and Euler angles (alpha, beta, gamma) describing the relative orientation of the quadrupolar and chemical shift tensorial frames. These measurements have been augmented with ab initio DFT calculations by using WIEN2k and NMR-CASTEP codes, which corroborate these reported values. Unlike previous assertions made about the inability to detect CSA (chemical shift anisotropy) contributions from Nb(V) in most oxo environments, this study emphasises that a thorough variable B(0) approach coupled with the VOCS (variable offset cumulative spectroscopy) technique for the acquisition of undistorted broad (-1/2<-->+1/2) central transition resonances facilitates the unambiguous observation of both quadrupolar and CSA contributions within these (93)Nb broadline data. These measurements reveal that the (93)Nb electric field gradient tensor is a particularly sensitive measure of the immediate and extended environments of the Nb(V) positions, with C(Q) values in the 0 to >80 MHz range being measured; similarly, the delta(iso) (covering an approximately 250 ppm range) and Omega values (covering a 0 to approximately 800 ppm range) characteristic of these niobate systems are also sensitive to structural disposition. However, their systematic rationalisation in terms of the Nb-O bond angles and distances defining the immediate Nb(V) oxo environment is complicated by longer-range influences that usually involve other heavy elements comprising the structure. It has also been established in this study that the best computational method(s) of analysis for the (93)Nb NMR interaction parameters generated here are the all-electron WIEN2k and the gauge included projector augmented wave (GIPAW) NMR-CASTEP DFT approaches, which account for the short- and long-range symmetries, periodicities and interaction-potential characteristics for all elements (and particularly the heavy elements) in comparison with Gaussian 03 methods, which focus on terminated portions of the total structure.

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“…This is the main viewpoints of Li-vacancy model. In 1992, the experiment results of Iyi supported the Li-vacancy model [16], hereafter, many experiments such as ray and neutron diffraction [17,18], nuclear magnetic resonance [19], and Raman spectrum Kojima et al [20] verified that the Li-vacancy model is more reasonable than other modes. In this article, the phenomenon of the absorption edge shift is explained by Z *2 /r, where Z * =Z-Σs, Z * is the effective nuclear charge number and Z is the atomic number of the ion, i.e.…”

Section: Resultsmentioning

confidence: 91%

Structure defects and optical damage resistance in doubly doped In:Nd:LiNbO₃ crystal waveguide substrates

Zhen¹,

Zhao

2003

Cryst. Res. Technol.

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A series of In:Nd:LiNbO 3 crystals were grown by Czochralski technique and were made into waveguide substrates. The optical damage resistance of the In:Nd:LiNbO 3 waveguide substrates was characterized by measurement of the holographic method. The optical damage resistance of In (3.0mol %):Nd:LiNbO 3 was much higher than that of other In:Nd:LiNbO 3 . The ultraviolet-visible (UV-Vis) absorption spectra the In:Nd:LiNbO 3 crystals were measured and investigated. The structure defects were discussed in this paper to explain the enhance of the optical damage resistance in the In:Nd:LiNbO 3 crystals.

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Solid state NMR study supporting the lithium vacancy defect model in congruent lithium niobate

Cited by 71 publications

References 21 publications

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

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

A ⁹³Nb Solid‐State NMR and Density Functional Theory Study of Four‐ and Six‐Coordinate Niobate Systems

Structure defects and optical damage resistance in doubly doped In:Nd:LiNbO₃ crystal waveguide substrates

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Solid state NMR study supporting the lithium vacancy defect model in congruent lithium niobate

Cited by 71 publications

References 21 publications

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

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

A 93Nb Solid‐State NMR and Density Functional Theory Study of Four‐ and Six‐Coordinate Niobate Systems

Structure defects and optical damage resistance in doubly doped In:Nd:LiNbO3 crystal waveguide substrates

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A ⁹³Nb Solid‐State NMR and Density Functional Theory Study of Four‐ and Six‐Coordinate Niobate Systems

Structure defects and optical damage resistance in doubly doped In:Nd:LiNbO₃ crystal waveguide substrates