Real structure influencing the hydrogen defect chemistry in congruent LiNbO3 and LiTaO3

Köhler, Thomas; Mehner, Erik; Hanzig, Juliane; Gärtner, G.; Stöcker, Hartmut; Leisegang, Tilmann; Meyer, Dirk C.

doi:10.1016/j.jssc.2016.09.017

Cited by 17 publications

(35 citation statements)

References 68 publications

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“…Invariance of the lattice vibration region demonstrates that the crystal lattice remains unchanged upon the thermal treatment. The absorption band consisting of two components at 3462 cm −1 and 3483 cm −1 is attributed to the OH − stretching vibrations arising from the different hydrogen binding sites [23]. Based on the melting diagram reported in Ref.…”

Section: B 7 LI Nmrmentioning

confidence: 96%

“…Transmission measurements were performed in the direction parallel to the crystallographic c axis. A KRS-5 thallium iodide bromide infrared polarizer with a polarization of 99% was employed to measure the maximal stretching vibration under the same conditions with respect to the c axis in all samples, because of the anisotropic nature of the OH − stretching vibration [23].…”

Section: Ft-infrared Spectroscopymentioning

confidence: 99%

“…Based on the melting diagram reported in Ref. [6] and the dependence of the OH − stretching band on the LT crystal composition [23,33], the nonstoichiometry of the samples under study has been determined and found to be [Li]/[Ta] = 48.7/51.3. This value is in agreement with that published in literature for congruent LT [6].…”

Section: B 7 LI Nmrmentioning

confidence: 99%

“…Thus, Li deficiency and the structural isomorphism of LT and LN allows us to assume that the defect models proposed in literature for LN can be considered for LT. However, our recent investigations of lithium tantalate and lithium niobate using light polarization resolved FT-IR spectroscopy have showed that these materials can be characterized by different defect concentrations and intrinsic defect clusters, which are besides preferably decorated by hydrogen [23].…”

Section: Introductionmentioning

confidence: 99%

“…ESR enables us to detect paramagnetic centers, such as metal impurities, localized charge carriers, F-type centers, broken chemical bonds, and Ta 4+ ions. FT-IR is sensitive to the concentration of hydroxide groups and allows quantitative characterization of the crystal stoichiometry based on the position and broadening of OH − stretching vibrations [23,33].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the defect clusters in congruent lithium tantalate

Vyalikh

Zschornak

Köhler

et al. 2018

Phys. Rev. Materials

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A wide range of technological applications of lithium tantalate (LT) is closely related to the defect chemistry. In literature, several intrinsic defect models have been proposed. Here, using a combinational approach based on DFT and solid-state NMR, we demonstrate that distribution of electric field gradients (EFGs) can be employed as a fingerprint of a specific defect configuration. Analyzing the distribution of 7 Li EFGs, the FT-IR and electron spin resonance (ESR) spectra, and the 7 Li spin-lattice relaxation behavior, we have found that the congruent LT samples provided by two manufacturers show rather different defect concentrations and distributions although both were grown by the Czochralski method. After thermal treatment hydrogen out-diffusion and homogeneous distribution of other defects have been observed by ESR, NMR, and FT-IR. The defect structure in one of two congruent LT crystals after annealing has been identified and proved by defect formation energy considerations, whereas the more complex defect configuration, including the presence of extrinsic defects, has been suggested for the other LT sample. The approach of searching the EFG fingerprints from DFT calculations in NMR spectra can be applied for identifying the defect clusters in other complex oxides.

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Section: B 7 LI Nmrmentioning

confidence: 96%

Section: Ft-infrared Spectroscopymentioning

confidence: 99%

Section: B 7 LI Nmrmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of the defect clusters in congruent lithium tantalate

Vyalikh

Zschornak

Köhler

et al. 2018

Phys. Rev. Materials

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Structure and Luminescent Properties of Double‐Doped LiNbO₃:Zn:Mg Crystals

Tokko,

Kadetova,

Prusskii

et al. 2024

Physica Status Solidi (a)

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The correlation between photoluminescence in the near‐IR region and point defect centers in the LiNbO3 crystals co‐doped with Zn and Mg both by homogeneous and direct methods has been studied. X‐ray diffraction (XRD) analysis shows that the LiNbO3:Zn:Mg (4.68:0.9 mol%) crystal obtained by homogeneous doping has the least number of intrinsic defects compared to the others. It has been established that ZnLi defects stimulate photoluminescence (PL) in the near‐IR region of the luminescence spectrum in the LiNbO3:Zn:Mg crystals obtained by homogeneous doping. The LiNbO3:Zn:Mg (4.68:0.90 mol%) crystal has the maximum PL intensity and the LiNbO3:Zn:Mg (3.83:0.97 mol%) crystal has the minimum. Both crystals are doped homogeneously. Such defects as niobium vacancies (VNb) and niobium in the empty octahedron (Nboct) are suggested as luminescence quenchers in the co‐doped crystals.

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