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Journal ArticleDOI

Local structure of LiB3O5 single crystal from 7Li nuclear magnetic resonance

30 Sep 2003-Journal of Applied Physics (American Institute of Physics)-Vol. 94, Iss: 8, pp 5095-5099
TL;DR: In this paper, the local structure of LiB3O5 single crystal was investigated with 7Li (I=3/2) nuclear magnetic resonance measurements, and the quadrupole coupling constants and the asymmetry parameters were determined at room temperature and are e2qQ/h=143±1 kHz and η=0.6±0.1 for 7Li.
Abstract: The local structure of LiB3O5 single crystal was investigated with 7Li (I=3/2) nuclear magnetic resonance measurements. We observed four different spectra, which could be divided into two groups corresponding to two kinds of lithium atoms, LiA and LiB, lying at crystallographically equivalent sites and magnetically inequivalent sites. From these results, the quadrupole coupling constants and the asymmetry parameters were determined at room temperature and are e2qQ/h=143±1 kHz and η=0.6±0.1 for 7Li. The directions of the principal axes of the electric field gradient tensors were also determined. The spectra for the two groups have the same principal values of the electric field gradient tensor, but different orientations, and originate from magnetically inequivalent sites. Also, the 7Li spin-lattice relaxation rate was measured, and the measured relaxation rate was found to be proportional to the temperature. The temperature-dependent single phonon process is considered to be more effective than the Raman ...
Citations
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Journal ArticleDOI
TL;DR: In this paper, the results of experimental study and modeling of thermally stimulated recombination processes in undoped crystals of lithium borates Li 2 B 4 O 7 and LiB 3 O 5 were reported.

23 citations

Journal ArticleDOI
TL;DR: In this paper, the thermally stimulated recombination processes and luminescence in crystals of the lithium borate family Li6(Y,Gd,Eu)(BO3)3 have been investigated.
Abstract: The thermally stimulated recombination processes and luminescence in crystals of the lithium borate family Li6(Y,Gd,Eu)(BO3)3 have been investigated. The steady-state luminescence spectra under X-ray excitation (X-ray luminescence spectra), the temperature dependences of the X-ray luminescence intensity, and the glow curves for the Li6Gd(BO3)3, Li6Eu(BO3)3, Li6Y0.5Gd0.5(BO3)3: Eu, and Li6Gd(BO3)3: Eu compounds have been measured in the temperature range 90–500 K. In the X-ray luminescence spectra, the band at 312 nm corresponding to the 6 P J → 8 S 7/2 transitions in the Gd3+ ion and the group of lines at 580–700 nm due to the 5 D 0 → 7 F J transitions (J = 0–4) in the Eu3+ ion are dominant. For undoped crystals, the X-ray luminescence intensity of these bands increases by a factor of 15 with a change in the temperature from 100 to 400 K. The possible mechanisms providing the observed temperature dependence of the intensity and their relation to the specific features of energy transfer of electronic excitations in these crystals have been discussed. It has been revealed that the glow curves for all the crystals under investigation exhibit the main complex peak with the maximum at a temperature of 110–160 K and a number of weaker peaks with the composition and structure dependent on the crystal type. The nature of shallow trapping centers responsible for the thermally stimulated luminescence in the range below room temperature and their relation to defects in the lithium cation sublattice have been analyzed.

17 citations

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the correlation between the parameters of the quadrupole interaction, the number of 3-coordinated borons, T 1, and the NLO properties at the boron sites in these crystals.

7 citations

Journal ArticleDOI
TL;DR: In this article, the nuclear spin-lattice relaxation rates for 133C nucleus in Cs2CuCl4 and Cs 2CoCl4 single crystals grown using the slow evaporation method were measured as a function of temperature.

7 citations

Journal ArticleDOI
TL;DR: In this article, the thermoluminescence (TL), X-ray-induced luminescence, and numerical modeling techniques were used to study the thermally stimulated recombination process in both the crystal-fibers and single crystals of lithium-gadolinium orthoborate Li 6 GdB 3 O 9, and the results were analyzed in the temperature range from 90 to 500 k after irradiation with X-rays at 90 k.

6 citations

References
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TL;DR: In this article, the effect of changing the precession frequency of the magnetic field has been studied using NMR to study rate properties. But the effect is limited to the case of double and double resonance.
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Journal ArticleDOI
TL;DR: LiB3O5 as mentioned in this paper is a new nonlinear-optical crystal with a high damage threshold of 25 GW/cm2 (at 1.064 μm, 0.1 nsec) and a wide acceptance angle of 25 mrad for θ ≠ 90°.
Abstract: The boron–oxygen compound LiB3O5 is recognized as a new nonlinear-optical crystal. This follows theoretical calculations of the second-harmonic generation (SHG) coefficients using the anionic group theory and the complete neglect of differential overlap approximation to obtain the localized wave functions of component groups. An optically perfect single crystal with space group Pna21, grown at the Fujian Institute of Research on the Structure of Matter by the high-temperature flux method, is found to be transparent from 160 nm to 2.6 μm. It has a SHG coefficient comparable with that of β-BaB2O4 as well as two other outstanding advantages: a high damage threshold of 25 GW/cm2 (at 1.064 μm, 0.1 nsec) and a wide acceptance angle of 25 mrad for θ ≠ 90° and 95 mrad for θ = 90° with a 6-mm-long crystal.

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