• Title/Summary/Keyword: niobate

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Growth of potassium lithium niobate (KLN) single crystal with high $Nb_2O_5$content ($Nb_2O_5$함량이 높은 potassium lithium niobate(KLN) 단결정의 성장)

  • 강길영;윤종규
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.3
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    • pp.396-400
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    • 1998
  • The physical properties of KLN single crystals very significantly according to the $Nb_2O_5$ content in grown crystal, therefore, it is very important to control the composition of KLN single crystals. In this study, KLN single crystals of high content $Nb_2O_5$ were grown by temperature fluctuation and TSSG (Top-seeded solution growth) methods with increasing the $Nb_2O_5$ content of starting solution. To investigate the existence of defect due to the increase of $Nb_2O_5$ content, dielectric and optical properties were measured. Due to the increase of defects in grown KLN single crystal, the shift of cutoff-frequency to lower energy and a broad Curie range, which shows the DPT (diffuse phase transition) characteristics, were observed.

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TSSG growth, morphology and properties of potassium lithium niobate (KLN) crystals

  • Chong, Tow-Chong;Xu, Xue-Wu;Lian Li;Zhang, Guang-Yu;H. Kumagai;M. Hirano
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1999.06a
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    • pp.167-185
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    • 1999
  • In the present paper, KLN crystals have been grown along <001>, <100> and <110> directions by the top seeded solution growth (TSSG) method from Li-richer melts with different compositions. The morphologies of KLN crystals grown along different directions have been studied, and the well-developed facets have been unambiguously indexed using X-ray goniometer and stereographic projection analysis. The growth mechanism and defects such as cracks and inclusions were discussed on the basis of observations of facets on the crystal-melt interfaces. The crystal compositions were determined by chemical analysis method. The structure and lattice constants of KLN crystals were determined and calculated on the basis of XRD data by using TREOR90 and PIRUM programs. The Curie temperature and optical absorption were determined by dielectric constant peak and spectrum measurements, respectively. The blue SHG characteristics of a KLN sample were also investigated using a pulsed dye laser. PACS: 42.70.M;81.10;81.10A;42.65.K.

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TSSG growth, morphology and properties of potassium lithium niobate (KLN) crystals

  • Chong, Tow-Chong;Xu, Xue-Wu;Li, Lian;Zhang, Guang-Yu;Kumagai, H.;Hirano, M.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.4
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    • pp.396-401
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    • 1999
  • In the present paper, potassium lithium niobate(KLN) crystals have been grown along <001>, <100> and <110> directions by the top seeded solution growth (TSSG) method from Li-richer melts with different compositions. The morphologies of KLN crystals grown along different directions have been studied, and the well-developed facets have been unambiguously indexed using X-ray goniometer and stereographic projection analysis. The growth mechanism and defects such as cracks and inclusions were discussed on the basis of observations of facets on the crystal-solution interfaces. The crystal compositions were determined by a chemical analysis method. The structure and lattice constants of KLN crystals were determined and calculated on the basis of XRD data by using TREOR90 and PIRUM programs. The Curie temperature and optical absorption were determined by dielectric constant peak and spectrum measurements. respectively. The blue second harmonic generation (SHG) characteristics of KLN sample were also investigated using a pulsed dye laser.

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Second harmonic generation (SHG) properties of potassium lithium niobate crystals grown by $\mu$-PD method ($\mu$-PD법에 의해 육성한 KLN단결정의 제2고조파 발생(SHG) 특성)

  • ;Tsuguo Fukuda
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.5 no.2
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    • pp.94-99
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    • 1995
  • Potassium lithium niobate (KLN) crystals, grown by the micro pulling down $({\mu}-PD)$ method, have been considered on the interchange between incongruent melt composition and second harmonic generation (SHG) properties because of the sensitive interaction. Correlation between the composition of crystals and the wavelength of SHG applications from ultra - violet to green region was found. Also, the ${\mu}-PD KLN$ KLN crystals showed a homogeneity of noncritical phase matching and an excellent SHG property which is converted to blue laser light with half wavelength by the red irradiation.

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Magnetic Properties of Cr-doped LiNbO3 by Using the Projection Operator Technique

  • Park, Jung-Il;Lee, Hyeong-Rag;Lee, Haeng-Ki
    • Journal of Magnetics
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    • v.16 no.2
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    • pp.108-113
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    • 2011
  • The electron spin resonance lineshape (ESRLS) function for the electron spin resonance linewidth (ESRLW) of $Cr^{3+}$ (S = 3/2) in ferroelectric lithium niobate single crystals doped with 0.05 wt% of Cr, is obtained by using the projection operator technique (POT), developed by Argyres and Sigel. The ESRLS function is calculated to be axially symmetric about the c - axis and analyzed by using the spin Hamiltonian $H_{SP}={\mu}_B(B{\cdot}{^\leftrightarrow_{g}}{\cdot}S)+S{\cdot}{^\leftrightarrow_{D}}{\cdot}S$ with the parameters g = 1.972 and D = $0.395\;cm^{-1}$. In the ca plane, the linewidths show a strong angular dependence, whereas in the ab plane, they are independent of the angle. This result implies that the resonance center has an axial symmetry along the c - axis. Further, from the temperature dependence of the linewidths that is shown, it can be seen that the linewidths increase as the temperature increases, at a frequency of v = 9.27GHz. This result implies that the scattering effect increases with increasing temperature. Thus, the POT is considered to be more convenient to explain the scattering mechanism as in the case of other optical resonant systems.

Sr/Ba Ratio Dependence of Dielectric Characteristics in Strontium Barium NiobateCeramics (Sr/Ba 비에 따른 Strontium Barium Niobate 세라믹스의 유전특성)

  • 김명섭;이준형;김정주;이희영;조상희
    • Journal of the Korean Ceramic Society
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    • v.38 no.12
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    • pp.1167-1173
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    • 2001
  • The tetragonal tungsten bronze type of Sr$_{x}Ba_{1-x}Nb_{2}O_{6}$(SBN) (0.3$\le$x$\ge$0.7) ceramics was synthesized by the solid state reaction method, and the dielectric properties of SBN ceramics as a function of Sr/Ba ratio were examined. With increasing Sr/Ba ratio in SBN ceramics, the Curie temperature decreased and the maximum dielectric constant at the Curie temperature increased. The relaxor behavior of the SBN ceramics as a function of Sr/Ba ratio was quantitatively evaluated. More relaxor behavior of dielectric characteristics was observed as the ratio of Sr/Ba increased. The experimental results are explained with a viewpoint of crystallography of tungsten bronze structured SBN ceramics.

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