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 glycine doped bis thiourea cadmium chloride single crystal

Single crystal of 2 mol% glycine doped Bis Thiourea Cadmium Chloride, a semi organic nonlinear optical material has been grown by slow evaporation technique. Good quality single crystal with dimension 14 × 12 × 5 mm³ was harvested after 35 days. The influence of amino acid glycine was studied for 1, 2 and 3 mol% glycine doped Bis Thiourea Cadmium Chloride by Kurtz and Perry powder second harmonic generation test and compared with pure Bis Thiourea Cadmium Chloride which confirms the enhancement of second harmonic generation property of glycine doped Bis Thiourea Cadmium Chloride. The large enhancement was found for 2 mol% glycine doping. The grown crystal was characterized by various characterizations viz. single crystal X‐ray diffraction, energy dispersive X‐ray (EDAX), Fourier Transform Infrared Spectroscopy (FTIR) analysis, UV‐visible absorption, thermo gravimetric analysis (TGA). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Electron microscopic investigations on optical oxide single crystal

Scanning and transmission electron microscopic methods including energy dispersive X-ray spectrometry and reflection high energy electron diffraction as well, were used for the inspection of the growth, the shape-processing and the laser irradiation induced defects in pure and doped optical oxyde single crystals. Some general results will be presented and discussed in the light of theoretical predictions.     

Thermal and EPR investigations of thallium gallium disulphide single crystal

In this research, the results of the differential scanning calorimetry (DSC) and electron paramagnetic resonance (EPR) investigations of TlGaS₂ single crystal are presented. Specific heat capacity (C_p) anomalies of layered TlGaS₂ have been obtained by using a new DSC technique for such crystals. Remarkable heat capacity anomalies have been revealed at the temperatures of 137.7 K, 174.5 K and 238.5 K. It is found that the anomalies appear at maximum with a small deviation (by 3‐4%) from the regular values, and C_p discontinuity amounted to approximately 5%. Additionally, EPR spectra of Fe doped TlGaS₂ single crystals have been recorded at various temperatures down to 6 K for different orientations of the applied magnetic field. Transformations of present EPR spectra are not sufficient for the confirmation of structural phase transitions, in contrast to the cases in iso structural TlInS₂ and TlGaSe₂ compounds. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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 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.     

Structural and microhardness studies of pure and thiourea doped glycine phosphite single crystal

Ferroelectric Glycine Phosphite (GPI) crystal have been grown from aqueous solution employing the slow cooling technique. As the crystal solubility in water depends on temperature, single crystals were grown. Transparent, colourless crystals with habit morphology weighing about 8g were obtained with in a month. The same procedure was used to grow single crystals of 10 wt% of Thiourea doped GPI (TUGPI). Formation of a new crystal was confirmed by Powder X‐ray diffraction studies as well as FTIR studies. Crystalline quality were found using rocking curve for both the crystals. Due to the presence of Thiourea in TUGPI, it improves the crystalline perfection and also enhances the growth rate. The variation of hardness on (010) faces of monoclinic GPI and TUGPI crystals, with load were studied.Vickers hardness numbers, H_v were found to decrease with the increase in load. The value of Mayer's index, ‘n ’ was found to be greater than 1.6 for GPI and TUGPI showing soft‐material category. The results are discussed in detail. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of glycine picrate—Remarkable second-harmonic generation in centrosymmetric crystal

Remarkable second-harmonic generation (SHG) efficiency has been observed in the glycine picrate (GP) though it crystallizes in centrosymmetric structure. Bulk single crystals of GP with a good size of ~20×10×3 mm³ have been successfully grown by the slow cooling method in aqueous medium. Powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) and FT-Raman studies have confirmed, respectively, the crystal structure and functional groups of the grown crystal. Crystalline perfection of single crystals has been evaluated by high-resolution X-ray diffractometry (HRXRD) using a multicrystal X-ray diffractometer and found that the grown crystals are nearly perfect. Nonlinear optical (NLO) behavior of glycine picrate crystals has been studied for the first time by Kurtz powder technique and its second-harmonic generation efficiency is found to be 2.34 times higher than that of KDP. Transparency of crystals in UV–vis–NIR region has also been studied. Dielectric measurements have been carried out using an impedance analyzer over a wide range of frequency (100 Hz–3 MHz) at room temperature. The slight decrease in dielectric constant has been observed as the frequency is increased and the dielectric loss is very low for the entire frequency range. The ac conductivity is almost constant up to 1 MHz and sudden increase has been observed above this frequency.     

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 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)     

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.     

Growth of cadmium mercury thiocyanate dimethylsulphoxide single crystal for laser frequency doubling

This paper reports the growth of an organometallic nonlinear optical (NLO) complex crystal, Cadmium mercury thiocyanate dimethyl-sulphoxide (CdHg(SCN)₄(H₆CP₂OS)₂, CMTD), which was grown from aqueous solution by a temperature lowering method. Its powder SHG intensity is higher than that of CMTC. The crystal size of CMTD can reach 25×23×15mm³. The solubility curve, and solubility variation with pH value are also reported. The growth habits of crystals of CMTD grown under different conditions are discussed and the optimized condition for the growth CMTD using a temperature-lowering method from aqueous solution are also discussed.     

Growth of ZnSe single crystal by CVT method with self-moving convection shield

The self-moving convection shield was used in the growth of ZnSe single crystal by chemical vapor transport method using iodine as a transport agent. The reduction of the convection enables the growth of a 1-in diameter ZnSe single crystal. The incorporation efficiency of iodine on (1 1 1)B facet was proved to be larger than that on (1 0 0) facet. Impurity-hardening effect of incorporated iodine in the grown ZnSe crystal is also suggested.     

Effect of nickel sulphate hexahydrate addition on crystal growth,structural, optical and biological applications of glycine single crystals

In the present study, single crystals of α- and γ-glycine have been successfully grown in the presence of nickel sulphate hexahydrate as an additive for the first time by using slow solvent evaporation method. The analytical grade chemicals of glycine and nickel sulphate hexahydrate were taken in five different molar ratios: 1:0.2, 1:0.4, 1:0.6, 1:0.8 and 1:1 respectively to find out the α, and γ-polymorph of glycine. The lower molar proportion of nickel sulphate hexahydrate yield only α-polymorph whereas the higher molar proportion of nickel sulphate hexahydrate yields only γ-polymorph of glycine which was confirmed by powder XRD studies. UV–Visible–NIR transmittance spectra were recorded for the samples to analyze the transparency in visible and near infrared region (NIR). The optical band gap Eg was estimated for grown nickel sulphate hexahydrate (NSH) added glycine crystals using UV–Visible–Transmission study. Functional groups present in the sample were identified by FTIR spectroscopic analysis. The in vitro antimicrobial activities of the synthesized nickel sulphate added glycine single crystals were investigated against gram positive, gram negative bacterial strains using the agar disk diffusion method.     

Growth of bubble-free Ti-doped Al2O3 single crystal by the czochralski method

The behaviour of bubble entrapment in Ti-doped Al₂O₃ single crystals grown by the Czochralski method was studied from the view point of crystal growth conditions such as the crystal rotation rate and kinds of growth atmosphere. The entrapment of bubbles was not correlated with the shape of solid-liquid interface dependent on crystal rotation rate. We found that the use fo He atmosphere, instead of the conventional atmosphere such as Ar, suppresses the formation of bubbles.     

Growth and characterization of Ytterbium doped KGd(WO4)2 single crystal

Single crystals of Ytterbium doped KGd(WO₄)₂ were grown by Top Seeded Solution Growth technique using K₂WO₄ as flux system. The growth parameters were optimised to get optically transparent crystals. Variation in the lattice parameters were observed in comparison to the pure KGd(WO₄)₂ crystals. The absorption spectra recorded for the Yb:KGW confirms the material suitability for diode pumped solid state lasers. The vibrational studies carried out using spontaneous Raman spectra indicate the strong anionic vibration of the material. PL spectra show the lasing channel of the laser active ions present. Stimulated Raman scattering analysis confirms the material as an efficient Raman laser material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)