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Organic nonlinear-optical single-crystal methyl p-hydroxybenzoate (MPHB) is one of the potential candidates for use in terahertz applications. The focus of this work is to study the response of MPHB single crystal in the terahertz region of the electromagnetic spectrum using time-domain terahertz spectroscopy (THz-TDS). Single-crystal MPHB was grown by the conventional slow evaporation solution growth technique (SEST). The structural confirmation of the title compound was assessed by powder x-ray diffraction (PXRD) analysis. The optical bandgap of ingot crystal was calculated using Tauc’s equation based on ultraviolet–visible (UV–Vis) spectroscopy. The photoluminescence emission spectrum revealed a major emission in the blue region corresponding to 457 nm. The dominant color emission for the title compound was assessed by converting the major emission peak to a Commission Internationale de l’Eclairage (CIE) chromaticity diagram, which further confirmed the emission of blue light from the crystal. The dynamics of the photon emission and its decay time for the title compound were studied by time-resolved photoluminescence (TRPL). THz-TDS was performed in the range from 0.2 THz to 3.0 THz on the title single crystal to observe its optical absorption behavior in the THz energy range. The variation of the absorption coefficient at terahertz frequencies is also presented herein.

Potassium dihydrogen phosphate (KH2PO4; KDP) is a well known nonlinear optical (NLO) material for optoelectronic, laser technology and fiber optical communication device applications. In a view to yeild better device properties, l-Phenylalanine (l-Phe) aminoacid doped KDP (LKDP) crystals with different dopant concentrations (0.5 mol%, 1 mol% and 2 mol %) were grown by slow evaporation solution technique (SEST). The grown crystals were powdered of micron size crystallites and subjected to powder X-ray diffraction (PXRD). In PXRD spectra, a few peaks with increasing intensity were observed in LKDP crystals when compared to pure KDP, revealing the effect of incorporation of dopants in the crystalline matrix of KDP and the enhancement of growth rate along [100] direction. FT-IR spectrum confirms the incorparation of dopant in KDP crystalline matrix with the presence of different vibrational modes of assignments belongs to L-Phe. To study the crystalline perfection of pure and doped crystals, the high-resolution X-ray diffraction (HRXRD) was employed and the crystalline perfection was found to be reasonably good with relatively low values of FWHM. UV–Vis-NIR spectroscopy results show significant increase in optical transmission up to ~ 80% from ~ 60% (pure KDP) in the entire visible spectrum of l-Phe doped KDP at low doping concentration. However, it was decreased to ~ 70% when we increase the dopant concentration by 2 mol% and suggests that if we increase the dopant (l-Phe) concentration above an optimal value in KDP, the transmission decreases. The Photoluminescence (PL) spectrum reveals high crystalline perfection at low concentration of dopants as observed by the sharp peaks. The weak green emission peak for sample with higher dopant concentrations indicates the segregation of doped molecules at the structural grain boundaries as observed in the HRXRD studies. The mechanical strength of pure and doped KDP crystals with increasing dopant concentration has been studied and found that the hardness was increased slightly due to doping. The powdered sample of micron size particle made from as grown crystals were subjected to Kurtz powder technique to observe the relative second harmonic generation (SHG) efficiency in comparison with the pure KDP. These results reveal significant enhancement of SHG efficiency with increasing doping concentration up to 2 mol% in KDP crystals which is 1.31 times to that of pure KDP.

This work focuses on the bulk growth of Itaconic acid (ITA) single crystal from aqueous solution by slow evaporation solution growth technique. The detailed structural, optical, laser studies have been carried out for the title compound by adopting different instrumentation techniques. The cut-off wavelength of ITA crystal was obtained at 268 nm shows good nonlinear response. From the PL measurement, the high intense emission peak was observed at 442 nm corresponds to blue emission. The dominant emission colour of the grown specimen was estimated by CIE plot. The fast and slow decay of ITA single crystal were studied by time resolved PL. The laser resistive nature was examined by Nd-YAG laser and found that it is having good laser damage threshold (LDT) property. The third-order nonlinear optical behaviour of ITA crystal has been analyzed with the help of a femto-second laser using Z-scan technique. The value of various parameters like nonlinear refractive index (n2) and nonlinear absorption coefficient (β) is estimated using the theoretical calculations. The values of n2 and β were found to be 3.13 $$\times$$ 10–17 cm2/W and 1.57 $$\times$$ 10–12 cm/W, respectively. Such values of nonlinear parameters shows that grown crystal can be useful in optoelectronics applications.

Optical grade semi-organic single crystal of sodium acid phthalate (NaAP) was synthesized, and the crystals were harvested by slow evaporation solution growth technique (SEST) in an ambient condition. The titled compound is a promising material for nonlinear optical (NLO) applications and crystallized in non-centrosymmetric system. The structural information of the above-mentioned crystal was investigated by powder X-ray diffraction (PXRD), which reveals that it belongs to orthorhombic structure and B2ab space group. The presence of defects in the harvested crystal was assessed by high-resolution X-ray diffraction (HRXRD) and found that grown single crystal is moderately good. The optical behaviour of NaAP crystal was examined by UV–Vis, photoluminescence (PL) and time-resolved PL (TRPL), respectively. Thermal response and stability of the title compound were tested using thermogravimetry (TG), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC) analyses. The coefficient of thermal expansion (CTE) was evaluated using thermomechanical analyzer (TMA). The third-order NLO properties of NaAP single crystal had been evaluated by Z-scan method. The two-photon absorption coefficient (β) was calculated from open-aperture curve of Z-scan. The nonlinear study reveals that NaAP crystal is an appropriate choice in optical limiting usage. Terahertz (THz) time domain spectroscopy was used to study optical characteristics like refractive index and absorption coefficient of NaAP single crystal.

In the present study, we have focused on the growth of semi-organic single crystals, as they play a vital role in the generation of a terahertz pulse and its potential applications. The single crystals of l-histidine hydrochloride monohydrate (LMHCL) were grown by slow evaporation solution growth by using deionized water as a solvent in a controlled atmosphere. Good quality crystals of the required size were obtained within 2 weeks. To estimate the lattice dimensions and get the structural information, powder x-ray diffraction (PXRD) study was performed in which we have found that the crystal belongs to the orthorhombic crystal system with space group P212121. The functional groups and the corresponding vibrational mode were confirmed using Fourier transform infrared (FTIR) and Raman spectroscopy, respectively. To study the optical properties UV–Vis transmission spectrum and photoluminescence (PL) were recorded. It was observed that the single crystal has a high value of transmission over a long range of wavelength which signifies that the crystal is a good candidate for nonlinear optical (NLO) applications. The UV cut-off wavelength is found to be 236 nm. The grown single crystals were studied by time-domain terahertz spectroscopy (THz-TDS) for photonic applications and the refractive indices were calculated and it is found that the refractive index is nearly equal to 3.4.

A semi-organic l-tyrosine hydrobromide (LTHB) nonlinear optical single crystal has been harvested using slow evaporation solution technique (SEST) at atmospheric conditions. The ingot has under gone for different characterisations to check its appropriateness for device fabrications. The structural conformation and unit cell dimensions have been estimated using powder X-ray diffraction (PXRD) method. The prominent peaks of PXRD have been indexed and it shows that crystal having non-centrosymmetric in nature with nonlinear optical application in second harmonic generation (SHG). Fourier-transform infrared spectroscopy (FTIR) analysis has been employed to characterise as grown crystal to know about the presence of various functional group in it. The crystalline quality and defects during the growth have been inspected by high resolution X-ray diffraction (HRXRD) technique. Optical studies have been carried out using UV–Vis and photoluminescence (PL) analysis. From UV–Vis measurement, we found that the material exhibits lower cut off wavelength with a high transparency window which is suitable for nonlinear optical (NLO) and optoelectronic applications. A detailed discussion of thermo gravimetric (TG) and derivative thermogravimetry (DTG) along with differential scanning calorimetry (DSC) has been presented to know about the thermal behaviour of LTHB crystal. The thermo mechanical analyser (TMA) which is useful to evaluate the coefficient of thermal expansion (CTE) of the grown crystal has been performed. Laser damage threshold (LDT) density has been noticed to check its strength for high intense laser. The optical, structural, thermal and phase matching studies of titled crystal establish the suitability of this material for optoelectronics and NLO device applications.

A bulk-sized single crystal of sulphamic acid (SA) was grown by the solution growth technique. The lattice dimensions and the plane’s identification of the grown crystal were confirmed with powder X-ray diffraction. High-resolution X-ray diffraction was employed to observe crystalline perfection that was found fairly good. The optical transmission studies reveal its suitability for optical applications in the complete UV–visible region of the electromagnetic spectrum. Bandgap calculations and other optical parameters like absorption and extinction coefficient were calculated to scrutinize its optical characteristics. The photoluminescence emission spectrum was recorded for the corresponding excitation wavelength to reveal the crystal behavior and energy gap transitions. The presence of the titled compound was examined through FTIR spectroscopy. Ellipsometry study was also carried out for the measurement of linear refractive index (n) and also for the extinction coefficient (K). Z-scan studies have been examined to reveal third-order nonlinear optical behavior and calculated the value of its nonlinear absorption coefficient (β). The Terahertz response of the grown crystal was analyzed by the terahertz time-domain spectroscopy. Observed results showed that SA crystal is a good aspirant for NLO applications.

An optical material is a fundamental in the field of information along with measurement of laser applications. Crystals of organic compounds are very well known for its highly efficient behavior towards the optical activities. In the present study, slow evaporation solution growth technique has been adopted for the growth of l-tartaric acid (LTA). The phase and structural information was assessed with powder X-ray diffraction and grown single crystal’s quality was tested through high resolution X-ray diffraction and found to be reasonably good. The composition bonding between the molecules was revealed out by Fourier-Transform Infrared Spectroscopy method. The Ultraviolet–Visible spectroscopy exposes the excellent transmittance properties of LTA crystal. Photoluminescence spectrum shows strong emission in the violet region. Optical properties are measured to know its behavior towards electromagnetic spectrum which is further analyzed by ultrafast pump probe spectrometry and the determination of non-linear optical absorption coefficient was also taken into account with respect to the absorbance spectra. Moreover, Vickers microhardness studies were carried out to check its mechanical behavior.

The mechanical properties of undoped and 2.0, 4.0 and 6.0 mol% Mg-doped LN single crystals, grown by the Czochralski technique, have been investigated using nanoindentation studies to understand the mechanical deformation behaviour as doping is increased. This has been correlated with structural investigations by powder XRD analysis and Raman spectroscopy. Powder X-ray diffraction measurements show a slight increase in the lattice parameters as the Mg content is increased in the crystal. The lattice strain developed due to the doping has been calculated by the Williamson-Hall relation. The influence of Mg incorporation on lattice vibrations was analysed using Raman spectroscopy, which indicated no shift in the peak positions with doping, and only slight variation in the intensity and width of the peaks. The grown crystals were subjected to nanoindentation and the Young's modulus and hardness values were obtained by using the Oliver-Pharr method. The results reveal the optimal doping levels of Mg which result in enhanced mechanical strength of lithium niobate single crystals.

Nonlinear optical materials (NLO) have been garnering attention due to their role in optical data storage, optical communication and laser technology. Organic crystals have emerged as an ex...

In the present technologically advanced era, non-linear optical materials especially organic derivatives are in the limelight due to their fast response in electro-optic switches and high nonlinear efficiency. Therefore, with respect to this behaviour, single crystals of L-argininium Bis(trifluoroacetate) (here in after called LABTF) an organic material was grown by slow evaporation solution growth technique. The grown single crystal was subjected to single crystal X-Ray diffractometer to validate its chemical structure and compound formation. The titled compound crystallizes into an asymmetric entity that comprises of one divalent L-argininium cation and two monovalent trifluoroacetic anion. All the intermolecular hydrogen bonds present in the LABTF crystal structure are investigated by 3D molecular Hirshfeld surface analysis and their relative involvements are disintegrated using 2D fingerprint plots. Further, the crystalline perfection assessment was performed using high-resolution X-Ray diffractometer which divulges the absence of structural grain boundaries in the obtained crystal. Thermal transport parameters of the titled compound were measured through Photoacoustic spectroscopy. The shock strength above which the crystal induces damage was found by the shock damage threshold technique. In addition, mechanical property related parameters such as hardness, stiffness and Young's Modulus were evaluated using the nanoindentation technique. These mechanical parameters resolve the reliability of devices and it can be enhanced by improving the crystal quality.

This work reports the synthesis of varied shaped Cu2ZnSnS4 (CZTS) nano inks in a most stable kesterite phase via a hot injection colloidal route. CZTS nanoparticles of varied shape were synthesized by using various capping ligands with the introduction of butylamine as a new capping ligand and two different sulfur precursors respectively. The shape of the as-synthesized kesterite CZTS nanocrystals can be well controlled in the form of nanofibers, spherical nanoparticles, nano hexagons, nanotriangles, and nanodiscs. A detailed analysis of the effects of various capping ligand and sulfur source on reaction conditions to obtain pure phase kesterite CZTS nanocrystals for different shapes is explained using LaMer's diagram. It has been found that the choice of sulfur precursor also plays an important role in determining the symmetry and orientation of the plane of the CZTS nanocrystals. Due to different morphology and capping ligands present on the surface, diverse surface properties were obtained which was confirmed by contact angle measurements. The variation in the band gap was also found with changes in morphology of kesterite phased CZTS nanoparticles. Due to variations obtained in band gap, changes in I-V characteristics were also observed which may leads different CZTS nanoparticles to have their potential applications in different regime other than photovoltaics like sensors, photocatalysis etc.

The controlled synthesis of CdSe/ZnO-nanocomposite fabrication by facile chemical route has been successfully performed. Crystalline structure was examined by XRD patterns, while the morphology was investigated was carried out using typical electron microscopic investigations of SEM and HR-TEM equipped with electron dispersion spectroscopy (EDS) analogous to the detection of chemical elements in hybrid composite. The typical SEM image of fabricated CdSe/ZnO-nanomaterial and the grain size was found to 12 nm. The elemental composition of CdSe/ZnO-nanomaterial was analyzed by energy dispersive X-ray spectrometry (EDS). The HR-TEM images of CdSe/ZnO NPs confirm the agglomerated particles neck with their neighbors and form hexagonal shapes. The UV–visible absorption spectroscopy was used to analyze the optical properties. From UV absorption spectrum, a broad peak at 405 nm was observed. The photoluminescence (PL) spectrum was also used to determine the optical properties. The PL spectrum shows the maximum was slightly red-shifted to 625 nm. At various frequencies and at an ambient condition of temperatures, the dielectric studies such as dielectric constant, dielectric loss and AC conductivity properties were investigated. Furthermore, we have studied the current density–voltage of CdSe/ZnO-nanocomposite.

Today the fundamental aspect of the researchers is to explore maximum physical properties of the material for device fabrication. In the present article, single crystal X-ray diffraction has been carried out to verify the formation of the synthesized compound. In addition to that, powder X-ray diffraction has been performed to obtain diffraction pattern of l -Prolinium Picrate single crystal. The strain present inside the single crystal was measured using Hall-Williamson equation from PXRD measurements. The dark current and photon current was obtained from photoconductivity technique whose plot depicted that the sample was negative photoconducting material. Optical homogeneity of the single crystal was analyzed using birefringence technique. Its resistance towards Nd: YAG laser was scrutinized for l -Prolinium Picrate single crystal by applying 1 pulse per second. Different thermal parameters like thermal conductivity, thermal diffusivity, thermal effusivity and specific heat were computed using photo-pyroelectric technique. Solid state parameters were calculated from Clausius Mossotti relation by taking structural information of the title compound. Also, optical parameters like refractive index, reflectance etc were calculated through UV–Vis–NIR analysis.

We report on the growth of N-benzyl-2-methyl-4-nitroaniline (BNA) crystals by a solution growth method using certain polar protic and aprotic solvents (single or mixed). It was observed that the morphology of the BNA crystals could be influenced by the solvents used and that the growth was, with certain exceptions, predominant along the crystallographic b axis. Attempts to grow large BNA crystals from these solvents showed that the majority of these polar solvent molecules tended to get adsorbed preferentially along the polar +c and/or −c axes/axis. The bulk and surface qualities of the grown crystals were observed to be influenced by the solvents employed to grow the BNA crystals and the results of THz measurements obtained for the crystals grown from selected solvents were also found to corroborate these observations. A systematic approach has shown that the BNA crystals grown from one of the polar aprotic solvents, which is presumably reported for the first time for this crystal, exhibited a relatively higher THz efficiency. It is further understood that this particular solvent created a favorable solute–solvent environment at the progressing crystal–solution interface which improved the overall quality of the BNA single crystals and resulted in the significant enhancement in the THz efficiencies.

In the present work we report crystallization and detailed analyses on l-arginine monohydrochloride single crystal an efficient material for nonlinear optical applications. The crystal of titled material was grown using slow evaporation solution growth technique using double distilled water as solvent. Single crystal X-ray diffraction technique revealed that lattice dimensions of grown crystal are in good agreement with the reported literature and it crystallised in monoclinic crystal system. High resolution X-ray diffraction study revealed that crystalline perfection is fairly good. Optical homogeneity and variation of birefringence across the sample cross-section was studied using birefringence interferometer. Specific heat and thermal conductivity of grown crystal was measured using photopyroelectric technique and was found to be higher than many organic and inorganic crystals. Its various mechanical properties and resistance toward deformation was examined using nano-indentation technique. Further laser damage threshold value and phase matching angle was also measured.

High efficiency thermoelectric materials plays a vital role in power generation and refrigeration applications. Bismuth telluride (Bi2Te3) is one among them. In the present work single crystal of bismuth telluride was grown using vertical Bridgman technique. The phase of grown crystals was analysed using a powder X-ray diffractometer. Quality of the grown crystal was assessed by using high resolution X-ray diffractometer and observed that it is fairly good. Further mechanical investigations on grown crystal was carried out using nano-indentation technique and various mechanical properties like hardness, stiffness and Young’s modulus were evaluated. Observed results clearly indicate its suitability for thermoelectric applications.

Benzimidazole single crystals were grown using a vertical Bridgman technique with modified ampoule design. The thermal fluctuations during the melt were effectively controlled by the glass ampoule support which was filled with alumina wool in order to maintain a proper temperature gradient throughout the growth process. The unit cell dimensions of the grown crystals were assessed using powder X-ray diffraction technique. Comparative analyses have been carried out for both the crystals which were grown using a conventional ampoule and using the ampoule with support, via high resolution X-ray diffraction and it was found that there was a significant enhancement in crystalline perfection for the crystal which was grown using the ampoule with support. Further, optical transmission and photoluminescence studies on the grown crystals were carried out using UV-vis and photoluminescence spectroscopy and it was observed that there was a noticeable variation in the optical transmission and luminescence results.

Long afterglow SrAl2O4:Eu2+,Dy3+ nanophosphors were synthesized via a facile but effectual auto-combustion technique followed by post-annealing treatment at elevated temperatures. The influence of various fuels during synthesis and thereafter improvement in the luminescence decay characteristics under various illuminant irradiations of long afterglow nanophosphors have been reported. Extensive studies on structural, morphological and luminescent properties of the as-synthesized afterglow nanophosphors have been presented. Powder X-ray diffraction studies confirm the presence of high-purity, single-phase monoclinic nanophosphors. HRTEM investigations confirm the formation of nanophosphors of particle size less than 50 nm. Photoluminescence emission is attributed to the characteristic d–f transition (4f65d1→4f7) of Eu2+ ions and was positioned at 512 nm. As-synthesized nanophosphors exhibit considerable confinement effects resulting into blue shift in emission maxima as compared to their bulk counterparts. The mechanism underlined for long afterglow has been discussed using trapping–detrapping model. The nanophosphor being multifunctional finds many interesting applications including dark-vision display, energy storage, fingerprint detection, in vivo and in vitro biological staining, etc.

A process for developing long-length joint tube assembly of Bi-2223 (10 wt% Ag) superconductor is presented. The process involves sintering of tubes fabricated from cold isostatic pressing of the partially preformed Bi-2223 (10 wt% Ag) superconducting powder. The joint was made between these sintered tubes. For making joints, sintered tubes were physically joined by connecting together on a common superconducting bush coated with a superconducting paste. Subsequently, the combination of the bush and the physically joined portion were sintered. The superconducting properties and phase identification/phase composition of the component tubes and of the joint portions have been investigated. The diametral fractural strength of the component tubes and of the joint portion was also evaluated. In the joint obtained according to this method, it is possible to retain the superconducting properties and the fractural strength of the joint high-temperature superconducting tubes. This technique is very useful for fabrication of very large sized superconducting apparatuses such as external magnetic shielding, transmission cables and electrical current leads, etc.

A single crystal of L-prolinium tartrate (LPT), which is an organic non linear optical material, was successfully synthesized and grown using a slow evaporation solution growth technique (SEST). The crystal structure and lattice parameters of the crystal were confirmed by powder X-ray diffraction and it was found that it belongs to the monoclinic crystal system with β = 100.380 and a noncentrosymmetric space group. The presence of strain in the grown ingot was calculated from powder X-ray diffraction measurements. The crystalline perfection was examined by high resolution X-ray diffractometry, which revealed that the crystal contained structural grain boundaries. The optical behavior of the grown specimen was analyzed by photoluminescence (PL) spectroscopy and its time resolved PL decay was calculated. The grown crystal adopted a step wise growth pattern with parallel striations, which was confirmed from the etching technique. Its ferroelectric and piezoelectric properties were also assessed. Its third order non linearity was assessed using an open aperture Z-scan technique. The thermal parameters of the LPT single crystal were calculated using a photopyroelectric technique. The mechanical strength of the single crystal at the micro level was observed by nanoindentation using the Oliver–Pharr method.

Single crystals of pure and l -tartaric acid (LTA) C4H6O6 doped ammonium dihydrogen phosphate (ADP) (NH4) H2PO4 were grown by slow evaporation solution technique (SEST) at ambient conditions. Powder X-ray diffraction (PXRD) analysis was carried out to confirm the crystal structure and no additional phase was observed due to doping except a systematic variation in peak intensities. Fourier transform infrared spectral analysis was done to examine the presence of various functional groups in the grown crystals. UV–VIS–NIR spectroscopic analysis was carried out to see the change in optical transparency of pure ADP and crystals due to LTA with different doping concentrations. Second harmonic generation (SHG) efficiency measurement was done to examine the enhancement in the nonlinear optical characteristics of the grown crystals. The effect of LTA dopant on crystal morphology, thermal and mechanical properties of ADP have also been presented in this paper. The above studies reveal the effect of incorporation of LTA into the lattice of ADP crystals.

Sol–gel-derived aluminum (Al)-doped zinc oxide thin films have been deposited on silicon (Si) wafers and microslide glass substrates using the spin coating technique. The atomic ratio of Al:Zn in the films is 0.05, 0.1, 0.2, and 0.3. The films have been characterized using different techniques, i.e., x-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy, UV-visible-near infrared spectrophotometry, spectroscopic ellipsometry, and the four-probe method. The films have exhibited excellent optical transmittance (∼90%). The refractive indices of the films are in the range between 1.47 and 1.53. The thickness of the films is in the range of 103–115 nm. The films have demonstrated reflectivity of about 3% at a wave length of 600 nm. The reflectivity, transmittance, refractive index, and thickness values of the films show that the films are promising candidates for utility as antireflection coatings in silicon solar cells.

Sulfamic acid (SA) single crystals, both pure and doped with 1, 2.5 and 5 mol% Nd, were grown successfully in an aqueous solution by the slow cooling method. Powder X-ray diffraction patterns were recorded to check the variation in the lattice parameters and phase of the crystals. The optical transparency was found to be higProd. Type: FTPhest (∼80%) for the 1 mol% Nd3+ doped SA single crystal. The optical band gap was also calculated and found to be ∼4.31, 4.20 and 3.67 eV. The influence of Nd3+ doping on the crystalline perfection was assessed by a high resolution X-ray diffractometer (HRXRD) and shows that the grown crystals could accommodate Nd3+ at the interstitial positions in the crystalline matrix of SA up to some critical concentration without any deterioration in the crystalline perfection. The etching studies were carried out and the etch pits densities were calculated. The mechanical property of grown single crystals was also studied.

In the present work, we have grown single crystals of l -proline cadmium chloride monohydrate (LPCCM) by slow evaporation solution technique (SEST) at room temperature and recorded their live growth kinetics with the help of inverted microscope. Crystal size at various stages of growth and its corresponding morphology was also recorded. Powder X-ray diffraction (PXRD) analysis of LPCCM single crystals confirmed the orthorhombic structure. Respective values of crystallite size, strain and dislocation density have been calculated using PXRD data. Metal complex coordination of the single crystal is studied by FTIR spectroscopic. The optical properties of the grown crystals were investigated through UV–VIS spectroscopic studies and shows that the crystals have very low absorption in entire characterized wavelength range 200–800 nm. The optical band gap was calculated and found to be ∼5.6 eV. Optical constants of the material is determined by theoretical calculations. The chemical etching study was also carried out to study the density of defects in the grown crystals. The photoluminous excitation and emission spectra and thermal property by TGA/DTA curve were recorded. Further, the mechanical properties have been studied using Vicker's microhardness tester as well as many parameters such as fracture toughness (Kc), Brittleness index (Bi) and yield strength (σν) are presented. Dielectric studies have been carried out with varying frequency and temperatures.

The potential organic nonlinear optical material of hippuric acid (HA) single crystal has been grown by the slow evaporation solution growth technique using N, N-dimethylformamide as the solvent. Single crystals of pure HA were irradiated at room temperature with 100 keV Nitrogen (N+) ions at fluence 1×1016 and 5×1016 ions/cm2. The pure and irradiated HA single crystals were characterized by different characterization technique. The photoluminescence and UV–visible absorption were performed at room temperature. The crystalline perfection of the pure and irradiated single crystals has been examined by high-resolution X-ray diffraction. Vickers microhardness technique was used to study the effect on the mechanical strength of the crystal at different ion fluences. The structural changes were analyzed by powder X-ray diffraction analysis. The functional groups of the synthesized compound have been identified by Fourier transform infrared spectroscopy. The dielectric constant and dielectric loss as a function...

Organic nonlinear optical crystal, 8-hydroxyquinolinium hydrogen maleate (8-HQM) with a dimension of 30×4×4 mm 3 was grown by the slow evaporation solution growth technique. The cell parameters of grown crystal were confirmed by single crystal X-ray diffraction analysis and it belongs to the noncentrosymmetric space group P2 1 2 1 2 1 . The crystalline perfection of 8-HQM crystal was examined by high resolution X-ray diffraction studies. UV–vis transmittance studies confirm the optical transparency window in the (480–900 nm) region. The TGA/DTA thermal measurements reveal that 8-HQM is thermally stable up to 160 °C. The laser damage threshold value of 8-HQM crystal was estimated to be 1.2 GW/cm 2 using a Nd:YAG laser. The relative second harmonic generation efficiency of 8-HQM crystal was found to be seven times greater than that of KDP.

The title compound of iminodiacetic acid hydrochloride (IDAAMHCL) has been successfully synthesized by adopting conventional chemical reaction and the single crystals have been grown by solvent evaporation method at room temperature and studied its various properties and reported for the first time. The lattice dimension and the crystal structure were identified from the powder X-ray diffraction analysis. The crystalline perfection assessed by high resolution X-ray diffraction technique shows that the specimen is free from structural grain boundaries. The presence of functional groups and the protons in IDAAMHCl was confirmed by Fourier transform infra-red and NMR (1H and 13C) spectroscopic techniques. The presence of carbon, hydrogen, and nitrogen was confirmed by elemental analysis. The optical behavior of IDAAMHCl was assessed by UV-visible spectroscopy and it is found that there is no absorption in the entire visible region of the spectrum. The Z scan measurements at 532 nm with 5 ns laser pulses show that IDAAMHCL is a very good candidate for optical limiting applications.

In the present work we focus on the coexistence of magnetic-electronic phases and hence phase separation in La 1 − x Ca x MnO 3 thin films in the composition range of 0.45 ≤ x ≤ 0.60. The oriented polycrystalline thin films were prepared by nebulized spray pyrolysis technique on single crystalline substrate LaAlO 3 [LAO (0 0 1)]. The lattice parameters are observed to decrease with increasing in Ca content and the structural/microstructural disorder is also seen to increase concomitantly. As the Ca content is increased from x = 0.45 to 0.55, the paramagnetic insulator (PMI) to ferromagnetic metal (FMM) transition temperatures ( T C / T IM ) are suppressed. This is accompanied by (i) appreciable suppression of the T C , (ii) sharp reduction in the magnetic moment, (iii) occurrence of a peak in the magnetization below T C , (iv) stronger bifurcation of the ZFC–FC magnetization, and (v) decline in the magnetization in the lower temperature regime. At x = 0.60, the FMM disappears and a weak FM insulator like phase is observed. In the vicinity of x = 0.55, the magnetic ground state resembles spin cluster glass. This is also confirmed by the occurrence of a hysteresis loop in the resistivity of the x = 0.55 measured during the cooling and warming cycle. The transition broadening up to x = 0.55 and the vanishing of the two transitions in x = 0.60 film along with the simultaneous decrease in the magnetic moment and enhanced resistivity show that the observed variations are due to the increase in the antiferromagnetic-charge ordered (AFM-CO) phase fraction at higher Ca content. This is also confirmed by the decrease in magnitude of the magnetoresistance and its temperature dependence. Our results demonstrate that, there is strong phase separation in the overdoped region (0.50 x ≤ 0.60) due to the presence of multiple magneto-electric phases.

Organic scintillation materials are very much useful in the area of nuclear experiments, medical diagnostics and therapy. In the present investigation, we have systematically analyzed the vertical Bridgman grown organic scintillation material of trans-stilbene which is annealed at different annealing temperatures. Remarkable changes have been observed on its structural and optical properties. High resolution X-ray diffraction (HRXRD) analysis shows noticeable difference for the annealed specimen than the as-grown crystal. The observed results exposed that the crystalline quality was drastically improved by the elimination of defects or low angle boundaries by post growth annealing technique. Its optical behavior has been examined by photoluminescence, Raman and IR analyses. Vickers microhardness measurement has been carried out and found that hardness values increases for the annealed trans-stilbene single crystals.

Transparent single crystals of diglycine cad- mium chloride were grown by slow evaporation solution technique. To confirm the crystal structure, the grown crystals were subjected to single crystal as well as powder X-ray diffraction measurements and the structure was found to be monoclinic. The elemental analysis was carried out by energy dispersive X-ray spectroscopy. The crystal- line perfection of the grown crystal was assessed by high- resolution X-ray diffractometry and found that the crystal quality is fairly good. The optical study reveals that the grown crystal is highly transparent in the region 250-900 nm. Thermal studies reveal that the grown crystal is stable up to 245 C. The michrohardness analysis revealed that the grown crystal belongs to soft material category. The high dielectric constant ((30) and low loss (\0.01) value also confirms that the grown crystal is a good candidate for device fabrications.

Gamma glycine was synthesized and the single crystals were grown by the slow evaporation method in the presence of lithium nitrate. Structure and crystalline nature of the grown γ-glycine crystal was confirmed by X-ray diffraction technique. It was found to crystallize in the trigonal system with space group P31. The chemical composition was determined by NMR. Fourier transform infrared studies revealed the functional groups present in the grown crystal and UV–vis–NIR spectra revealed the transmission properties of the crystal specimen. Surface morphology of the grown crystal was studied by scanning electron microscopy (SEM) and elemental composition was confirmed by energy-dispersive spectrometry (EDS). The second-order nonlinear optical property of the material was investigated by Kurtz powder technique and the relative second harmonic efficiency of γ-glycine was estimated to be higher than that of KDP. The dielectric measurement was carried out as a function of frequencies at room temperature and the results were discussed. The samples have shown piezoelectric behavior with a fairly good piezoelectric charge coefficient (d33) of 7.37 pC/N. Photoluminescence studies showed emission peak around 350 nm. Thermo gravimetric and differential thermal analyses were employed to understand the thermal and physio-chemical stability of the synthesized compound.

FT-Raman, IR and UV–vis spectroscopies have been applied to investigate the potential nonlinear optical (NLO) material N-(2 chlorophenyl)-1-propanamide. A detailed interpretation of the vibrational spectra was carried out with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. Density functional theory is applied to explore the nonlinear optical properties of the molecule. The study suggests the importance of π-conjugated systems for nonlinear optical properties and the possibility of charge transfer interactions. Good consistency is found between the calculated results and experimental data for the electronic absorption, IR and Raman spectra. The solvent effects have been calculated using time-dependent density functional theory in combination with the polarized continuum model, and the results are in good agreement with experimental measurements.

Modern development of optical devices calls for new nonlinear optical (NLO) materials with extraordinary properties. Organic and semi-organic materials are getting considerable attention because of their potential uses in various optical telecommunication devices including optical modulation, optical switching and optical limiters. The Z-scan technique is a simple and sensitive single beam method to determine both the nonlinear refractive index and nonlinear absorption coefficient of materials. In this investigation Z scan was performed on potassium acid phthalate (KHP) and methyl p-hydroxybenzoate (p-MHB) single crystals by using Nd: YAG laser at 532 nm. The results were analyzed and compared. The outcome of this investigation could help us to learn the material completely and also to understand the relations between molecular structure, linear absorption and optical nonlinearity the crystals. The entire outcome of this work suggests that KHP and p-MHB are potential materials for optical device application.

The effect of surface preparation on CdZnTe properties was investigated. Surface etching using bromine solutions enhances Te elemental composition, resulting in a Te rich surface layer that is prone to oxidize. This oxidation degrades the performance of the fabricated CZT gamma detector. Roughness results were identical for samples polished with 1 and 3 μm and subsequently etched in 2% Br-MeOH. The optimal concentration of etching was 2% Br-MeOH.

Bulk CZT crystals doped with Bi (1 x 10(19) at/cm(3)) have been grown by the Oscillatory Bridgman method, the growth velocity and the zinc concentration profile being improved by the insertion of a Pt tube acting as a cold finger. The stoichiometric uniformity was examined by energy dispersive X-ray analysis, and the zinc concentration was confirmed by inductively coupled plasma mass spectroscopy and cathodoluminescence measurements. The resistivity value was in the range of 8 x 10(8) Omega cm , being smaller for the passivated sample, which at the same time had counter device properties.

In the present scenario, nonlinear optical single crystals are very much useful in the field of second harmonic generation, fibre optic communication, electro-optic modulation, etc. In order to satisfy the above said requirements, crystal researchers have to find out novel and efficient nonlinear optical materials. In the recent past semi-organic materials are more attractive because of its dual characteristics of organic and inorganic systems. In the present communication, we have successfully synthesized the semi-organic nonlinear optical material of l-histidine bromide (LHB) and the single crystal has been grown by slow evaporation solution growth technique. The formation of the synthesized compound was confirmed by Fourier transform infrared (FTIR) analysis and the lattice dimensions have been determined from the powder X-ray diffraction analysis. Its crystalline perfection was examined by high-resolution X-ray diffractometer (HRXRD) and found to be an excellent. Its refractive index and birefringence have been studied. Its optical and electrical properties have been assessed by UV–vis, photoluminescence and dielectric measurements, respectively. Its laser damage threshold was determined by adopting Nd:YAG laser as a source.

The semi-organic nonlinear optical single crystal of L-glutamic acid hydrochloride was grown by slow evaporation solution growth technique at room temperature. The cell parameters of the grown crystal were estimated by single crystal X-ray diffraction analysis. The presence of various functional groups was identified from Fourier transform infrared analysis. The transmission spectrum of this crystal show that the lower cut-off wavelength lies at 248 nm. Thermal analysis was performed to study the thermal stability of the grown crystal. The Kurtz powder second harmonic generation test shows that the crystal is a potential candidate for optical second harmonic generation. Mechanical properties of the grown crystal were determined and Vickers' hardness number was calculated.

Unidirectional benzophenone single crystals grown by vertical Bridgman (VB), microtube-Czochralski (μT-CZ), uniaxially solution crystallization method of Sankaranarayanan–Ramasamy (SR) were characterized using X-ray diffraction (XRD), high-resolution XRD (HRXRD), laser damage threshold (LDT) studies and the results were compared. The XRD study exhibits the growth direction of the benzophenone crystal ingots. The HRXRD curves recorded by multicrystal X-ray diffractometer (MCD) revealed that the crystals grown by all the three methods contain internal structural grain boundaries. The SR grown sample shows relatively good crystalline nature with the full-width half-maximum (FWHM) of the main peak of 39 arcsec. While, the VB grown crystal contain multiple low-angle (α⩾1 arcmin) grain boundaries, probably due to thermal stress during post-growth annealing caused by the difference in the lattice expansion coefficients of the crystal and the ampoule, whereas such thermal stress are absent in μT-CZ grown sample due to the free standing nature of the grown crystal. Hence, the μT-CZ grown crystals contain only one very low-angle (α

Single crystals of a new semi-organic nonlinear optical material glycine hydrobromide were grown from solution by slow evaporation at room temperature. Good optical quality single crystals with dimensions 17×8×5 mm3 were obtained. The grown crystal had been confirmed by single-crystal X-ray diffraction and the vibrational frequencies of various functional groups in the crystals had been derived from Fourier transform infrared spectrum. The optical quality of the grown crystals was analyzed by the Ultraviolet visible spectrum method. The mechanical behavior of the grown crystal was evaluated by Vickers' micro-hardness indentation method. The nonlinear optical property of the crystal was confirmed by the Kurtz powder technique using Nd : YAG laser as a source.

The nucleation parameters such as, energy per unit volume, radius of critical nucleus, critical free energy barrier, number of molecules in the critical nucleus and nucleation rate have been evaluated for bis glycine sodium nitrate single crystals. The interfacial energy of the solution at various temperatures has been estimated from existing solubility data. The metastable zone width and induction period measurements have been carried out experimentally.

A novel organometallic nonlinear optical (NLO) crystal, namely thiourea complex of tetrakis thiourea potassium iodide (TTPI), has been grown by slow evaporation solution growth technique. The harvested crystal is large in size. To our knowledge there is no report is available for the bulk size single crystal of TTPI. This material has a positive temperature coefficient and has been grown by slow evaporation solution growth technique. The grown crystal have been characterized by employing several techniques such as single crystal and powder X-ray diffraction, FTIR, UV-Vis-NIR spectra, thermo gravimetric analyses respectively. Etching studies have also been carried out in order to know the surface defects on the as grown specimen of TTPI. The relative second harmonic generation efficiency have been tested by using Nd:YAG laser as source. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The 50 MeV Si ion irradiation-induced modifications on structural, chemical, optical and thermal properties of Vertical Bridgman grown benzimidazole (BMZ) crystals have been studied. The FTIR studies have been used to analyze the variation in various bonds that are associated with the functional groups in the native and the irradiated sample. X-ray diffraction studies reveal the compressive strains that are generated due to irradiation. The effect of irradiation on the conductivity of BMZ crystals has been studied. The fluorescence spectrum shows the existence of some energy levels, which remains unaffected after irradiation. The thermal analysis reveals that the melting point remains unaffected and the sample does not decompose as a result of irradiation.

Single crystals of a new nonlinear optical material, cadmium zinc thiourea acetate (CZTA), were successfully grown by slow evaporation of the aqueous solution at room temperature. Single crystal X-ray diffraction pattern and FTIR spectrum analysis have confirmed the formation of the new crystal. The optical transmission studies and second harmonic generation (SHG) efficiency studies justified the device quality of the grown crystals.

The bulk organic single crystal of phthalic anhydride (PA) was grown by vertical Bridgman technique. The structural perfection of the grown crystal was analysed by high resolution X-ray diffraction (Multicrystal X-ray diffractometry) studies. The thermal and mechanical properties have been studied. The second harmonic generation relative efficiency of Phthalic anhydride crystal is compared with KDP crystal. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Single crystals of para Nitroaniline ( pNA ), an organic nonlinear optical (NLO) material, have been grown by slow solvent evaporation technique at room temperature. Good optical quality single crystals with dimensions of up to 10 × 11 × 3 mm 3 have been grown by adopting the above technique, and good quality single crystals were obtained. The grown single crystals were subjected to different characterization analyses. The lattice dimensions have been determined from the powder X-ray diffraction analysis. Its functional groups and optical behavior have been identified from the FTIR and UV-Vis. analyses respectively. The thermal stability of the crystal has been analyzed by thermogravimetric (TG) and differential thermal (DT) analyses respectively.

The 50 MeV Si7+ ion irradiation induced modifications on structural, dielectric, optical and mechanical properties of Vertical Bridgman grown benzimidazole (BMZ) crystals were studied. The high resolution X-ray diffraction studies show the quality of as grown BMZ and irradiated BMZ crystals. The dielectric constant and dielectric loss as a function of frequency and temperature was studied in detail. The ion induced mechanical behaviour of both as grown BMZ and irradiated BMZ crystals has been explained with the indentation effects using Vickers microhardness tester. UV-VIS. studies reveal the decrease in bandgap values and defects on irradiation. The above results are discussed in detail. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)