Synthesis,growth, morphology and characterization of ferroelectric glycine phosphite single crystals

Glycine phosphite (NH₃CH₂COO.H₃PO₃), a potential ferroelectric material, was grown as single crystals from aqueous solutions by slow evaporation and slow cooling methods. Laboratory synthesized title compound was purified by recrystallization method and confirmed by Fourier transform infrared and Laser Raman studies. Temperature dependent solubility in double distilled water in the range between 288 and 328 K was determined by gravimetric method. Morphological importance of various growth faces were studied by optical goniometry. Powder x‐ray diffraction study performed on the grown crystals confirms the crystal system and lattice parameters of the unit cell. Optical transparency of the grown crystals in the ultraviolet–visible ‐near infrared region was studied by spectroscopic method. Thermal stability of the grown crystals in the temperature region above ambient until melting was studied using differential scanning calorimetry. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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 succinic acid single crystals

Single crystals of ferroelectric succinic acid were grown from aqueous solution by low temperature solution growth technique. The cell parameters and space group are found using powder X‐ray diffraction analysis. The presence of the functional groups has been estimated qualitatively by FTIR analysis. The UV‐Visible spectrum shows the cut‐off wavelength at 240 nm. The thermal stability of the crystal was studied by TG/DTA. The dielectric constant of the crystal studied as a function of frequency shows the pyroelectric property. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Studies on large uniaxially grown benzophenone single crystals

〈110〉, 〈010〉 and 〈100〉 oriented uniaxial benzophenone crystals were grown by uniaxially solution‐crystallization method of Sankaranarayanan ‐ Ramasamy (SR). The experimental parameters involved in the present study were investigated in detail and a constant growth rate was achieved by compensating the loss of growth units in the solution. A transparent uniaxial benzophenone crystal having dimension of 500 mm length and 55 mm diameter was grown at room temperature for the first time in the literature. In contrast to the conventional solution growth method, the growth rate along each direction was measured at ease during the respective growth experiment by monitoring the elevation of the solid‐liquid interface and found to be 2, 4 and 6 mm/day along the 〈110〉, 〈010〉 and 〈100〉 directions respectively for a chosen supersaturation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Influence of La3+ ions on growth and NLO properties of KDP single crystals

Single crystals of pure and Lanthanum added KDP crystals were grown from aqueous solution. The influence of La³⁺ ions in KDP crystals is studied. Isolated centers are formed by La³⁺ ions in KDP structure along (100) plane. La³⁺ ions incorporated into superficial crystal growth layer and slightly affect the growth process as they generate weak lattice stresses. The creation of these weak lattice stress is confirmed by Vickers's micro hardness test. The HRXRD analysis showed reduced structural defects in the La added KDP in the (100) plane than pure KDP. The incorporation of La in the crystal was confirmed by EDAX analysis. The Kurtz's powder SHG efficiency was found to be 1.5 times that of pure KDP. The UV‐Vis transmission spectra of La added KDP showed excellent transmittance from 1100 nm to 340 nm and did not show any change in lower cutoff wavelength with respect to pure KDP. Laser damage threshold value has been determined using Q‐switched Nd:YAG laser operating at 1064 nm and with 65 ns pulses in single shot mode. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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)     

Crystal growth of PZN‐PT single crystals and critical issues for higher piezoelectric coefficient

Single crystals of lead zinc niobate‐lead titanate (1‐x)Pb(Zn_1/3Nb_2/3)O₃–xPbTiO₃ for x = 8% and 9% have been grown by flux method using Lead Oxide (PbO) as flux. Low scan rate XRD has been carried out to investigate on the structural influence of the compositional variations in the grown crystals. Transmission spectra in the range of UV‐Vis‐Near IR and mid IR regions have been carried out to understand the distortions caused in the BO₆ octahedral lattice. Morphological aspects of as‐grown PZN‐PT crystals have also been investigated. Dielectric measurements clearly explained the dependence of T_c and diffusiveness with PT content. The values of P_r and E_cobtained from P‐E loops suggest the presence of ordered domain state in these PZN‐PT single crystals. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth of dendritic cobalt nanocrystals at room temperature

Dendritic cobalt nanocrystals have been synthesized by the reduction of Co²⁺ with hydrazine hydrate in ethanol via a room temperature solution synthetic route. The magnetic coercivity H_c of as-prepared cobalt dendrites came up to 500 Oe at room temperature. We chose different solvents to control the phases and morphologies of the cobalt products.     

Nucleation kinetics and growth aspects of organic nonlinear optical L‐arginine trifluoroacetate single crystals

Experimental determination of solubility, metastable zonewidth and induction period for an organic nonlinear optical (NLO) L‐arginine trifluoroacetate (LATF) crystal is reported. The interfacial tension for different supersaturation conditions has been estimated for the LATF solution at 45°C. Bulk crystal of dimensions 57x5x3 mm³ has been grown by temperature lowering technique using optimized growth parameters. Powder X‐ray diffraction and FTIR studies confirm the crystalline nature and the functional groups of the grown crystals respectively. Linear optical property of the grown crystal has been studied by UV‐Vis spectrum. Thermal analyses have revealed that the compound is thermally stable upto 212°C. Kurtz powder SHG test confirm the nonlinear optical properties of the as‐grown LATF crystal. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of rhodium incorporation in KTiOPO4 single crystals grown from self‐flux

The presence of an impurity like rhodium in the platinum crucible used for the growth of KTiOPO₄ (KTP) single crystals can have severe consequences in the performance of devices made from these crystals. In the present study the effect of rhodium incorporation has been investigated. Rhodium‐incorporated KTP crystals have a lower ionic conductivity (1.3 × 10^–7 S/cm at 100 kHz) than pure KTP crystals (3.5 × 10^–6 S/cm at 100 kHz) along the c‐axis. And the optical absorption in the green‐wavelength regime leads to a detrimental effect on their SHG performance. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Optical and dielectric studies on succinic acid single crystals

Single crystals of ferroelectric succinic acid (SA) with very high degree of transparency were grown from aqueous solution by slow evaporation technique. Single crystal X‐ray diffraction analysis reveals that the crystal belongs to monoclinic system with the space group P2₁/c. Some physical parameters have been determined for grown crystal. The optical absorption study reveals the transparency of the crystal in the entire visible region and the cut off wave length was found to be 240 nm. The optical band gap is found to be 3.75 eV. The dependence of extinction coefficient (k) and refractive index (n) on the wavelength have also been reported. The presence of functional groups was determined qualitatively by using Fourier transform infrared spectrum (FTIR) from which force constant has been calculated. The dielectric constant was also studied as a function of frequency at room temperature and electrical conductivity has been calculated from the Cole‐Cole plot. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Solution growth and comparative characterization of L‐HFB single crystals

Single crystals of L‐histidine tetrafluoroborate (C₆H₁₀N₃O₂BF_{4 ,} L‐HFB) were grown by solution growth method using two different temperature profiles: conventional, in which the growth temperature was kept constant at 30°C and rapid, in which it was increased in steps of 1 K per day while keeping the other growth conditions same. Crystals grew in nearly 30 and 10 days in the two methods, respectively. The crystals were transparent and showing its characteristic morphology. Both types of crystals were characterized by XRD for their structural comparison. Surface morphology and growth features of the crystals were studied by SEM. Features of two dimensional layer growth steps, rectangular etch pits, slip lines and bands, etc. were observed. The presence of various functional groups and their bonding were studied by FTIR in the range 4000‐400 cm^‐1. Thermal stability of the crystals was determined by thermo‐gravimetric and differential thermal analysis. The generation of green light due to second harmonic generation for fundamental λ =1064 nm has been confirmed in both cases. Dielectric constant measurement was carried out in the range 20Hz‐2MHz. In the UV‐Vis studies, high transmittance and a shorter ‘lower cut off' value (232 nm) were observed. The effect of rapid growth on the structural, morphological and optical properties of the crystals were studied and compared to those of crystals grown in conventional way. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,growth and characterization of single crystals of pure and thiourea doped L‐glutamic acid hydrochloride

L(+)Glutamic acid hydrochloride [HOOC (CH₂)₂CH(NH₂) COOH·HCl], a monoamino dicarboxylic acid salt of L‐Glutamic acid was synthesized and the synthesis was confirmed by FTIR analysis. Solubility of the material in water was determined. Pure and Thiourea doped L‐Glutamic acid hydrochloride crystals were grown by low temperature solution growth using solvent evaporation technique. XRD, UV‐Vis‐NIR analyses were carried out for both pure and thiourea doped crystals. The crystals were qualitatively analyzed by EDAX analysis and the presence of thiourea was confirmed. The cell parameters of L‐Glutamic acid hydrochloride have been determined as a = 5.151 Å, b = 11.79 Å, c = 13.35 Å by X‐ray diffraction analysis and it crystallizes in orthorhombic space group P2₁2₁2₁. UV‐Vis‐NIR spectra analysis showed good optical transmission in the entire visible region for both pure and doped crystals. Micro hardness of both pure and doped crystals has been determined using Vickers micro hardness tester. The SHG efficiencies of both pure and doped crystals were determined using Kurtz powder test and pure L‐Glutamic acid hydrochloride crystal was found to possess better efficiency than thiourea doped L‐Glutamic acid hydrochloride crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Solubility and crystallization of BaHPO4 crystals

A study of growth of barium hydrogen phosphate (BaHPO₄) crystal from solution is reported. The raw materials of barium hydrogen phosphate were successfully synthesized through chemical reaction in water. The solubility in HCl and H₃PO₄ solution were studied. It increased when acid concentration and temperature become higher, and the fitted curve of solubility is nearly a line. The acid concentration affects crystalline morphology of BaHPO₄ crystal. The crystallization is well when the acid solution ranges from 0.5 to 0.8M. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Growth of benzophenone single crystals from solution: A novel approach with 100% solute ‐ crystal conversion efficiency

An unidirectional 60mm diameter benzophenone single crystal was successfully grown by utilizing a novel crystal growth method at room temperature. <110> oriented single crystal ingots were grown out of xylene as solvent and by fixing a seed at the bottom of the ampoule. The obtained benzophenone ingots with the sizes of 10mm, 25mm and 60mm diameter evident that ease in increasing the diameter of the ingot. The orientation of the ingot and the crystalline quality were justified by X‐ray studies. TG and DTA evaluated the thermal properties of the grown crystal. The optical transmission study and the powder SHG measurement show the suitability of the ingot for nonlinear optical applications. The achieved solute‐crystal conversion efficiency of hundred percent shows vital advantage of this technique for cost effectiveness. The microbial growth as in the case of amino acid based growth solutions can be more effectively controlled in the present method since the freshly prepared growth solution can be constantly made available to the growing crystal. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Optical imaging of the growth kinetics and polar morphology of zinc tris(thiourea) sulphate single crystals

Growth kinetics of zinc tris(thiourea) sulphate (ZTS) single crystals was imaged in two different growth geometries using laser shadowgraphy technique. Growth rates of the {010} and {001} faces were computed as a function of supersaturation. The time evolution of polar morphology of ZTS crystal based on the growth rates is presented. Except (00 ) face, all the other three faces are found to have a dead zone resulting in large induction period of growth. The anisotropy in the growth rates of the (001) and (00 ) faces was very high, resulting in polar morphology. Different chemical environments on two sides of the (001) slice are suggested as the possible cause for the polar morphology of the crystals. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nucleation kinetics and growth of nonlinear optical bis (dimethyl sulfoxide) manganese mercury thiocyanate single crystals

Nonlinear optical (NLO) material of bis (dimethyl sulfoxide) manganese mercury thiocyanate (MMTD) was synthesized by two step reaction method. The solubility and metastable zonewidth were experimentally determined in order to optimize the growth parameters. Bulk crystals of MMTD were grown by slow cooling and slow evaporation methods. The structure of the grown crystal was confirmed by X‐ray diffraction analysis. Presence of functional groups and the coordination of Lewis base ligand of dimethyl sulfoxide (DMSO) were confirmed by FT‐IR analysis. Optical transparency of the grown crystals was studied by UV‐Vis spectroscopy. Nonlinear optical property of the grown crystal was confirmed by Kurtz powder method. Etching studies reveal the formation of triangular hillock etch patterns, indicative of 2D nucleation mechanism. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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.     

Solution growth and morphology of CH3NH3PbBr3 single crystals in different solvents

In this work, large‐sized CH₃NH₃PbBr₃ single crystals were successful grown using solution evaporation method with hydrohalic acid and N, N‐Dimethylformamide (DMF) as solvent respectively. The lattice parameters of cubic CH₃NH₃PbBr₃ were estimated using XRD method. The solubility of CH₃NH₃PbBr₃ in hydrobromic acid was determined at the temperature range between 20 °C–90 °C. A special micro‐solution crystallizer was designed to in‐situ study the morphology of CH₃NH₃PbBr₃ crystal. The largest crystal face was indexed by the XRD patterns and it would be {110} for CH₃NH₃PbBr₃ grown from HBr solution and {100} from DMF solution. The results show that solvent would affect the morphology and crystal habit greatly during crystal growth from solution.