Fluorine-Ionic Conductivity of Superionic Conductor Crystals Na0.37Tb0.63F2.26

Crystallography Reports - The temperature dependence (in the range of 479–827 K) of the fluorine-ionic conductivity of nonstoichiometric Na0.37Tb0.63F2.26 crystals with fluorite-type...     

Growth and characterisation of Na3Sb2F9 single crystals

Optically clear single crystals of Na₃Sb₂F₉ have been grown from solution by slow evaporation technique at constant temperature. Crystals of sizes upto 30 × 8 × 8 mm have been grown in a period of three months. Vickers microhardness measurements have been carried out on these crystals. Attempts have also been made to understand the nature of the cracks developed around the microindentation. Single crystal X-ray diffraction studies have been carried out and cell parameters are determined.     

Growth and characterization of LiF single crystal fibers

Single crystal LiF fibers have been grown by the micro‐pulling‐down (µ‐PD) technique. The fibers are 0.6 mm in diameter and 100 mm in length and of good optical quality. We describe the experimental apparatus for growth and analyze the sample structure and its spectroscopic characteristics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and dichroic properties of LiBa12(BO3)7F4 crystal

The bulk crystals of LiBa₁₂(BO₃)₇F₄ were obtained from two flux compositions by the top seeded solution growth method. Crystals grown from BaCO₃:BaF₂:H₃BO₃:Li₂CO₃ = 3:3:3:1 charge were found to have a distinct linear dichroism effect at 0.35–0.65 and around 0.73 μm. This suggests application of the material in the production of polarizing filters and attenuators for visible range lasers.     

Growth and characteristic of Sr3Tb(BO3)3 crystal

A new borate single crystal of Sr₃Tb(BO₃)₃ with dimension Ф20×25 mm² has been grown by the Czochralski method. The grown crystal was characterized by DTA–TGA, FTIR and X-ray powder diffraction analysis. The results showed the crystal with [BO₃]^3? is congruently melting at 1351.35 °C which belongs to hexagonal structure. The hardness of Sr₃Tb(BO₃)₃ crystal is 422.5 VDH, and is equal to 5.0 moh. The thermal expansion coefficients were determined to be 2.08×10^?5/°C along (1 0 0) direction and 7.43×10^?6/°C along (0 0 1) direction and the transmission spectrum was measured in 320–1800 nm at room temperature. The magnetic properties of the single crystal were studied which showed its paramagnetism and magnetic anisotropy. The specific Faraday rotation of single crystal was measured at room temperature in 532, 633, and 1064 nm wavelength. The Verdet constants and magneto-optical figures of merit were investigated. The primary emphasis is laid to explore a new magneto-optical material, all the magneto-optical properties of Sr₃Tb(BO₃)₃ are comparing to the ones of TGG.     

Growth and characterization of glycine lithium sulphate single crystal

Single crystal of glycine lithium sulphate, a nonlinear optical material, was grown from aqua solution by temperature reduction method. The solubility and metastable zonewidth of glycine lithium sulphate were estimated using aqueous solution. The cell parameters of the grown crystal were estimated by single crystal X‐ ray diffraction analysis. The presence of functional groups was identified from FTIR spectrum. Thermal analysis was performed to study the thermal stability of the grown crystal. The transmission and absorption spectra of this crystal show that the lower cut off wavelength lies at 330 nm. Powder Second Harmonic Generation efficiency of the grown crystal measured by Kurtz technique is 0.75 times that of potassium dihydrogen orthophosphate. Vickers microhardness study was carried out on the well developed (011) face of the grown crystal. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of l-prolinium picrate single crystal: A promising NLO crystal

l-Prolinium picrate was synthesized and its solubility in the mixed solvent of acetone and water was estimated. Employing temperature reduction method crystals of size 22×4×3 mm³ were grown. The cell dimensions were obtained by single-crystal X-ray diffraction study. FT-IR, UV–vis–NIR and fluorescence spectral analyses were carried out for the grown crystals. The optical band gap estimated for this crystal is about 2.4 eV. Thermogravimetric study was carried out to determine the thermal properties of the grown crystal. Kurtz powder second harmonic generation (SHG) efficiency measurement revealed that the SHG efficiency is about 52 times that of potassium dihydrogen orthophosphate. Mechanical strength was tested by Vicker's microhardness test.     

Growth and dielectric properties of Ta2O5 single crystal by the floating zone method

Large Ta₂O₅ single crystal with high‐dielectric permittivity was successfully grown by floating zone (FZ) method under air atmosphere. The grown crystal that has been obtained was typically about 8 mm in diameter and 90 mm in length. The crystal growth parameters were optimized. The crystal symmetry, characterized by means of X‐ray diffraction (XRD), was found to be tetragonal. The relative permittivity and loss tangent along growth and [001] direction were measured in the temperature range between ‐200 °C and 200 °C, which showed a strong dielectric anisotropy. At a frequency of 1 MHz and 20 °C, the dielectric permittivity along the growth direction and [001] direction are 81.17 and 25.04 respectively. The stabilization of high‐temperature phase can explain the dielectric enhancement.     

Growth of large oriented metal single crystal plates

A method of growing large oriented metal single crystal plates is presented. Crystal plates without any mechanical treatment are suitable for neutron diffraction work. The mosaic spread of these crystals is smaller than that of cylindrical single crystals.     

Growth and characterization of near stoichiometric LiNbO3 single crystal

A near stoichiometric LiNbO₃ single crystal has been grown by the Czochralski method from a 58.5% Li melt hold in a large platinum crucible. High resolution X‐ray rocking curves of 30 0 and 0006 reflections indicated that the near stoichiometric LiNbO₃ crystal possesses the high structural quality. Compared with the congruent LiNbO₃, the near stoichiometric LiNbO₃ possesses shorter ultraviolet absorption edge, thus higher Li concentration. The OH^– infrared absorption band analyses showed that the Li concentration in the near stoichiometric LiNbO₃ crystal is higher than that in the congruent LiNbO₃ crystal. This result is in good agreement with that of the ultraviolet absorption edge. The electro‐optic (EO) coefficient γ₂₂ of the near stoichiometric LiNbO₃ crystal was measured to be 6.75 pm/V higher than that of congruent LiNbO₃ crystal. It also proves the near stoichiometric LiNbO₃ electro‐optic Q‐switched requires a low driving voltage and it is advantageous for the device performance. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Electrical properties of nitrogen implanted GaSe single crystal

N‐implantation to GaSe single crystals was carried out perpendicular to c‐axis with ion beam of 6 × 10¹⁵ ions/cm² dose having energy values 30 keV and 60 keV. Temperature dependent electrical conductivities and Hall mobilities of implanted samples were measured along the layer in the temperature range of 100‐320 K. It was observed that N‐implantation decreases the resistivity values down to 10³ Ω‐cm depending on the annealing temperature, from the room temperature resistivity values of as‐grown samples lying in the range 10⁶‐10⁷ Ω‐cm. The temperature dependent conductivities exhibits two regions (100‐190 and 200‐320 K) with the activation energies of 234‐267 meV and 26‐74 meV, for the annealing temperatures of 500 and 700 °C, respectively. The temperature dependence of Hall mobility for the sample annealed at 500 °C shows abrupt increase and decrease as the ambient temperature increases. The analysis of the mobility‐temperature dependence in the studied temperature range showed that impurity scattering and lattice scattering mechanisms are effective at different temperature regions with high temperature exponent. Annealing of the samples at 700 °C shifted impurity scattering mechanism toward higher temperature regions. In order to obtain the information about the defect produced by N‐implantation, the carrier density was analyzed by using single donor‐single acceptor model. We found acceptor ionization energy as E_a = 450 meV, and acceptor and donor concentration as 1.3 × 10¹³ and N_d = 3.5 × 10¹⁰ cm⁻³, respectively. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Li_(0.067)Na_(0.933)Tb(MoO_4)_2磁光晶体的生长与磁光性能

采用Czochralski法生长了Li_(0.067)Na_(0.933)Tb(MoO_4)_2晶体,并测试了Li~+在NaTb(MoO_4)_2晶体中的有效分凝系数.由粉末X射线衍射数据计算了晶体的晶胞参数.室温下,采用消光法测试了Li_(0.063)Na_(0.933)Tb(MoO_4)_2晶体在532 nm、633 nm和1064 nm处的费尔德常数,分别为-293.6 rad·m~(-1)·T~(-1)、-200.5 rad·m~(-1)·T~(-1)和-68.6 rad·m~(-1)·T~(-1),与纯NaTb(MoO_4)_2相比,其费尔德常数均有所增加.结果表明,在1064 nm处Li_(0.067)Na_(0.933)Tb(MoO_4)_2晶体有较高的磁光优值.     

Growth and properties of single crystals of FeTi

A Single crystal of FeTi with a diameter of ca 34 mm and a length of ca 48 mm has been grown from a quasi-stoichiometric melt with an excess of 1% titanium employing the Bridgman technique. Experiments with the Czochralski technique were not successful. The only crucible material sufficiently resistent against reaction with the melt is electrographite. Elastic and thermoelastic constants were determined by means of ultrasonic methods. FeTi and α iron possess a similar bulk compressibility, thermal expansion, and thermoelastic constants. The longitudinal elastic resistance c₁₁ of FeTi supersedes that of α iron by an amount of ca 30%.     

Growth and characterization of calcium lithium tantalum gallium garnet single crystal

A new disordered garnet single crystal, calcium lithium tantalum gallium garnet (CLTGG) was grown by the Czochralski method. The lattice parameter of the crystal has been determined to be a=12.508±0.001 Å by X-ray powder diffraction (XRPD). The melting point of CLTGG was measured to be 1548 °C. The crystal possesses a wide transmission range from the ultraviolet to infrared, which is advantageous for applications as a laser host material. The refractive indices were also measured by the V-prism method.     

Growth and spectroscopic characterization of Nd3BWO9 single crystal

Pure and ytterbium-doped neodymium borotungstate (Nd₃BWO₉, and Nd_2.85Yb_0.15BWO₉, respectively) single crystals have been grown by means of high-temperature solution growth method from 15 mol% solution in PbO. The phase of both crystals was confirmed to be hexagonal with acentric space group P6₃. Absorption and luminescence spectra as well as decay time for ⁴F_3/2→⁴I_11/2 transition in neodymium borotungstate were measured and discussed. The obtained results show that Nd₃BWO₉ is suitable as high-neodymium-content laser crystal for microchip laser applications.     

Growth and characterization of 2,6‐dibenzylidenecyclohexanone single crystal

Following the temperature reduction method, growth of single crystals of organic 2,6‐dibenzylidenecyclohexanone (DBCH) material from ethanol solution is reported in the present work. Solubility and metastable zone width measurements were carried out under stirring and nonstirring conditions of solution. Cell dimensions were obtained from single crystal X‐ray diffraction study. From FT‐IR spectral analysis, various functional groups of this crystal were identified. UV‐Visible spectral analysis was made. Mechanical strength of the grown crystal was estimated on the prominent (110) face using a Vickers microhardness tester. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of Imidazolium adipate (IA) single crystal

Bulk single crystals of Imidazolium adipate (IA) were grown by solution growth method at 35 °C temperature. The solubility measurement of the material was carried out. FT-IR spectral analysis confirms the functional groups of the IA compound. Linear and nonlinear optical properties of the crystal were analyzed by UV-Vis-NIR transmittance and SHG studies. The high transparency with wide band gap is useful for optoelectronic applications are indicated. The SHG efficiency was higher than KDP. Vickers hardness study confirmed that the crystal was soft nature. Thermal stability of the material is up to 80 °C and the electrical study was carried out.     

Isotropic lazurite: A cubic single crystal with an incommensurate three-dimensional modulation of the structure

The incommensurately modulated structure of the isotropic lazurite Na_6.41Ca_1.36K_0.04(Si_6.09Al_5.91)O₂₄(SO₄)_1.73Cl_0.17 from the Ba?kal region is solved in the (3 + 3)-dimensional symmetry group P23(γγ0) [where γ = 0.2154(1)] with the basic unit cell parameter a = 9.077(1) Å. The structure is refined to R ₀ = 0.04 for the main reflections and R ₁ = 0.15 for the satellite reflections. Six modulation waves are directed along the side diagonals of the unit cell. The structural model under investigation is compared with the twin model previously proposed for the same crystal. The structural data obtained are used to construct fragments of the modulated structure. Considering the constructed fragments of the modulated structure, it has become possible for the first time to reproduce and describe the three-dimensional modulation of the framework and to reveal its relation to modulations of intraframework atoms.     

Growth of Na modified potassium lithium niobate crystal by the Czochralski method

Transparent Na modified potassium lithium niobate (Na_0.23K_2.60Li_1.82Nb_5.35O_15.70; NKLN) crystal was successively grown by the Czochralski method using RF induction heating from melt composition Na₂O:K₂O : Li₂O:Nb₂O₅=2:30:25:43 mol%. NKLN crystal showed a tetragonal tungsten bronze structure with lattice constants a=12.5446±0.0010 Å and c=4.0129±0.0005 Å at room temperature. The dielectric constant along the c-axis ε₃₃ showed a sharp maximum around 480 °C. Optical transmission edge was 370 nm and optical transmission spectra showed no absorption at wavelengths ranging from 380 to 800 nm. The structural and optical properties of NKLN were similar to those of the near stoichiometric KLN crystals. We believe that the growth of NKLN by the Czochralski method has an advantage for a large size and high-quality crystal.     

Growth investigations of single crystal sulphates containing molecular glycine groups

Investigations on the optimalisation of the growth conditions of single crystals containing molecular glycine groups were performed and depending on the pH-value of the solution, crystals of triglycine sulphate, diglycine sulphate or diglycine sulphate monohydrate can be grown. The optimal pH-value for triglycine sulphate growing was found to be 1.5.