Triglycine Sulphate Single Crystals Research Articles

Investigations on theoretical models describing the load-indentation size dependence for (001), (010), (101), (1̄1̄1) and (1̄11) faces of triglycine sulphate

Ferroelectric triglycine sulphate (TGS) single crystals were grown by slow evaporation technique over a period of 30–40 days. The Vickers microhardness studies have been carried out on (001), (010), (101), ([Formula: see text][Formula: see text]1) and ([Formula: see text]11) faces of the TGS crystal. The as-grown (001) face and (010) face with the ferroelectric phase were used to study the temperature dependence of hardness. The indentation size effect (ISE) described using the five theoretical models viz., Meyer’s law, Hays–Kendall, elastic/plastic deformation (EPD), proportional specimen resistance (PSR) and modified PSR model has been investigated on all the crystal faces under study. The experimental results show that the modified PSR model is more accurate at generating load-independent hardness data and also for explaining the origin of ISE.

Effect of adding technologically processed antibodies to interferon-gamma into a parent solution on the structural features of triglycine sulfate crystals grown from this solution

Objectives. Ferroelectric triglycine sulfate (TGS) belongs to a group of crystals whose properties are sensitive even to minor changes in growth conditions. The mechanism of spontaneous polarization in TGS is associated with the adjustment of protons which participate in the formation of hydrogen bonds. Therefore, the state of the parent solution plays an important role in the crystal formation. The study aims to investigate the structural features of TGS crystals grown using aqueous alcoholic solutions of technologically processed antibodies to interferon-gamma, in comparison with those of the crystals grown using the control solutions (technologically processed phosphate-buffered saline and intact aqueous alcoholic solution).Methods. X-ray diffraction assay and Raman spectroscopy.Results. The effect of solutions of the technologically processed antibodies to interferongamma added to a parent solution on the growth of TGS single crystals is established. This effect manifests in the changing in occupancy of the proton sublattice of the crystal grown from the parent solution containing technologically processed antibodies to interferon-gamma, as compared with the crystals grown from the control solutions. In the case of the crystal grown from the solution containing technologically processed antibodies to interferon-gamma, this change in the occupancy of the proton lattice is expressed in an increase in the length of N2–C3 bonds.Conclusions. Adding the technologically processed antibodies in the parent solution before the crystal growth can affect the structure of TGS crystals.

Acoustic shock wave-induced ordered to disordered switchable phase transitions: A case study of ferroelectric triglycine sulphate single crystal for the application of molecular switches

Highly efficient switchable materials for external stimuli have impressive applications in the development of precious sensor devices. However, most of the materials do not possess effective switchable structural features such that finding potential switchable materials is one of the critical research tasks for materials science researchers. In the present research perspective, we demonstrate successive switchable phase transitions occurring between the order to disorder states in the ferroelectric triglycine sulphate (TGS) single crystal along the (011) plane with respect to the number of shock pulses (0,1 and 2 counts) and the observed results are evaluated by the diffraction, spectroscopic, microscopic and thermal approaches. The observed switchable phase transitions occur due to the shock wave-induced inter-conversion of planar configuration to the non-planar configuration of Glycine molecules, particularly GII and GIII. The ratio of the normalized Raman bands Sym-CH2/Asym-CH2 is found to be 2.0 and 2.5 for the respective order to disorder states such that these values are identified to be well-matched with the literature reports. In addition to that, the SEM images authenticate that, during the amorphous to crystalline phase transitions, the appearance of well-defined (011) plane on the surface is ensured due to the dynamic recrystallization. To the best of our knowledge, to date, it is probably the first report for the phase switching of order to disorder states of TGS sample by the impact of acoustical shock waves and because of its efficient switchability, it can be strongly suggested for the application of molecular switches.

Terahertz wave rectification in a ferroelectric triglycine sulfate single crystal.

The effect of optical rectification (OR) in the terahertz range (THz rectification, TR) is experimentally demonstrated. The effect consists of generating a DC voltage on the faces of a ferroelectric triglycine sulfate (TGS) single crystal under the action of pulsed radiation with a frequency of 1.57 and 1.96 THz and an electric field strength per pulse of 1.3 and 1.5 MV/m, respectively. The FLARE FELIX free-electron laser system (Radboud University, The Netherlands) was used as a THz radiation source. The TR effect makes it possible to directly determine the nonlinear susceptibilities of media (including those under conditions of strong absorption) without any reference or optical channel calibration and also without the need of Fourier transform.

In situ X-ray diffraction studies of deformation behavior of ferroelectric triglycine sulfate under uniaxial compression

A combination of high-resolution X-ray diffraction and X-ray diffraction topography was used for analysis and visualization of elastic strain in ferroelectric triglycine sulfate (TGS) single crystals under uniaxial compression. Diffraction peaks and topographs were obtained for both the 400 and 060 reflections of TGS in transmission geometry under gradually increased compression stress up to 3.5 MPa applied along the [100] and [010] crystallographic directions. All the diffraction data from the sample were obtained from the whole crystal volume with wide beam illumination. Analysis of diffraction patterns revealed a nonlinear increase in integral intensity versus stress and a linear increase in peak broadening versus stress for all compression measurement combinations. The topographs confirmed that the formation of uniform and non-uniform strain fields depended on the direction of crystal compression and its relationship with integral intensity. A twinning process was found for the in-plane reflection along the [100] direction. All the effects induced by compression were reversible after decompression of the sample. According to the results, a significant anisotropy of deformation processes depending on the crystallographic direction was observed, which can be explained by the proposed deformation mechanism with superposition of compression stress, the piezoelectric effect and ferroelectric domain evolution.

Highly Anisotropic Tip-Induced Domain Growth in Polydomain Triglycine Sulfate

Ferroelectrics are widely used as modern functional materials for nonlinear optics, optoelectronics, nonvolatile data storage, and nanoelectronics. Most of these applications require creation of precise micron-scale domain patterns. We have studied the current limited wall motion regime driven by anisotropic bulk screening processes during local switching in polydomain triglycine sulfate single crystals. The field application using a conductive tip of a scanning probe microscope (SPM) in a dry atmosphere resulted in formation of a partially switched area, strongly elongated in the c crystallographic direction. At the same time, switching at high humidity led to a circular shape of the area. The calculation of the spatial distribution of the external field demonstrated the possibility of domain wall shift at distances up to hundreds of microns from the SPM tip. However, after external field switch-off the depolarization field in nonscreened areas led to reverse domain wall motion. Thus, the domain wall stabilization is possible only in the regions with sufficient screening of the depolarization field. We have shown that the growth of the area size with time obeys the same current-limited wall motion expressions that were derived previously for domain growth during local switching by a highly resistive electrode. The change in the area shape with humidity was attributed to the change in the governing screening mechanism from anisotropic bulk conductivity to isotropic surface conductivity through an adsorbed water layer. The obtained results demonstrate the essential role of the screening processes during periodical poling and pave the way for further improvement of the domain engineering methods.

The Study of Structural, Optical, and Dielectric Properties of Magnesium Chloride-Doped Triglycine Sulphate Ferroelectric Single Crystals

Triglycine sulphate (TGS) and 1 and 2 mol% of magnesium chloride-doped TGS single crystals have been grown by using the slow evaporation solution method at room temperature. Pure and magnesium chloride-doped triglycine sulphate single crystals in a dimension of 12 × 12 × 5 cm3 have been grown at room temperature. The grown samples have been investigated by various characterization techniques such as single crystal X-ray diffraction, UV-VIS/NIR spectroscopy, dielectric studies, and energy dispersive X-ray analysis (EDAX). The single crystal X-ray diffraction studies revealed that both 1 and 2 mol% of MgCl2-doped TGS single crystals have been crystallized in monoclinic crystal structure with space group P21/m. The UV-VI/NIR spectra analysis confirmed that both pure and 1 and 2 mol% of MgCl2-doped TGS single crystals have wide optical transparency in the wavelength range of 236–1100 nm. The bandgap energy of both samples has been found to be 5.25 eV. The dielectric properties of the grown samples were recorded by measuring the dielectric constant as a function of temperature from 45 to 55°C with various frequencies (100 Hz – 1 MHz). The dielectric studies revealed that the dielectric constants of 1 and 2 mol% of MgCl2-doped TGS single crystals were increased with decreasing frequency and that the transition temperature was found to be 51°C. The EDAX spectrum confirmed the incorporation of MgCl2 into TGS single crystals.

Hirshfeld surface, etching, mechanical and electrical enhancement analyses of pyramid pattern of Xylenol Orange dye in Triglycine Sulphate single crystals

An organic dye as a guest in ferroelectric single crystal can be enhanced the optical, electrical and mechanical properties. The crystal structure of both TGS were estimated by single crystal X-ray diffraction. Hirshfeld surface, voids and fingerprint plot studies were performed to understand the intermolecular interactions of the TGS in graphical representation. The SEM and optical microscope observations of the chemically etched on faces (100) of both TGS crystals were revealed the presence of inverse triangular pyramid pits with dislocation density in order of 103–104 ​cm−2. The high mechanical stability and increased value in Curie temperature with low loss of dielectric permittivity were occurred in dyed TGS. A highly saturated P – E hysteresis loop and higher piezoelectric coefficients were observed in dyed TGS. The improved mechanical strength, dielectric, ferroelectric and piezoelectric properties make the dyed TGS single crystals better candidate for electronic devices.

Croconic Acid Doped Triglycine Sulfate: Crystal Structure, UV-Vis, FTIR, Raman, Photoluminescence Spectroscopy, and Dielectric Properties

Triglycine sulfate (TGS) single crystals doped with croconic acid (CA) were grown by evaporation from aqueous solutions. X-ray diffraction analysis shows a slight reduction in unit cell volume in TGS:CA compared to pure TGS crystals. The polarized Raman and near-infrared absorption spectra show that the positions of most lines resulting from inter- and intramolecular vibrations are in good agreement with those in spectra of undoped TGS crystals. The inclusion of CA in TGS is confirmed by the presence of bands characteristic of CA in the infrared-Fourier transform spectra. The ultraviolet-visible absorption spectra of TGS:CA are characterized by the presence of additional absorption bands (compared to the spectra of pure TGS) located in the transparent region of pure TGS. In the photon energy region 1.6–3.6 eV, a strong “green” luminescence band is present in TGS:CA upon excitation at λ = 325 nm. The position of the emission band depends on the wavelength of the exciting light. Doping of TGS with CA causes pinning of domain walls, which is accompanied by a decrease in amplitude and frequency dispersion of the dielectric anomaly at the phase transition, a decrease in the switchable polarization and an increase in the coercive field of hysteresis loops.

Unusual domain growth during local switching in triglycine sulfate crystals

Formation and growth of isolated lenticular domains created by local switching using a biased tip of the scanning probe microscope in nominally pure triglycine sulfate single crystals have been studied experimentally. The obtained unusual change in the domain shape during growth has been considered in terms of a kinetic approach and attributed to simultaneous stochastic step generation for domain widening and deterministic nucleation (step generation at the domain vertices) for domain elongation. The main parameters of the domain wall motion have been extracted by fitting of the field dependence of the domain length and width. The obtained results provide a useful insight into the features of the domain structure kinetics in the uniaxial ferroelectrics and can be used for development of the domain engineering methods.

Effect of surfactants on the growth and characterization of triglycine sulfate crystals

This study investigates the effect on crystal growth and physical properties of triglycine sulfate (TGS) single crystals grown in the presence of surfactants, namely the anionic surfactants sodium dodecyl sulfate (SDS) and sodium 1-decanesulfonate (S1-DS). Pure TGS as well as SDS_TGS and S1-DS_TGS single crystals have been grown from aqueous solution, using a temperature lowering technique. The use of surfactants affects both crystal growth rate and shape. Concerning the latter feature, SDS_TGS crystals show larger (010) faces (b-face) and the S1-DS_TGS crystals show an elongation in [010] direction (b-direction). All samples are monoclinic and show the same Curie temperature (49 °C) as pure TGS. The UV–Vis transmittance of the crystals is found to be decreased due to the presence of surfactants during the growth process. At room temperature, the relative permittivity of the samples is decreased from 10.5 for pure TGS to 7.5 and 5.5 for SDS_TGS and S1-DS_TGS crystals, respectively. However, all crystals show the same pyroelectric coefficient of 168 μC/(m2·K) at room temperature. With that, the pyroelectric voltage figure of merit (FOM) (pc/ (ε.ε0)) is increased from 201 kV/(m·K)for pure TGS up to 245 kV/(m·K) for SDS_TGS, and up to 317 kV/(m·K)for S1-DS_TGS. The energy harvesting figure of merit(pc2/ε·ε0) is increased from 30.37 J/(m3.K2) for pure TGS to 42.52 and 58 J/(m3.K2) for SDS_TGS and S1-DS_TGS crystals, respectively.

Influence of nickel (Ni7+) Swift Heavy Ion (SHI) irradiation on the optical, topological, dielectric, piezoelectric and ferroelectric properties of 〈0 1 1〉 oriented ferroelectric triglycine sulphate single crystals

Nickel (Ni7+) Swift Heavy Ion (SHI) irradiation effects on the optical, topological, dielectric, piezo- electric and ferroelectric properties of 〈011〉 oriented ferroelectric Triglycine sulphate (TGS) single crystals have been investigated. Dielectric constant found to have increased more than 9 fold upon irradiation. A marginal shift in Tc (325–332 K) has been noted upon irradiation. A significant improvement in the piezoelectric coefficient has been observed for irradiated samples when compared to the 〈011〉 pristine TGS. Ferroelectric studies reveal the decrease in coercive field due to the irradiation with Ni7+ ions. The results obtained from all studies have been discussed in detail.

DIELECTRIC RELAXATION PHENOMENA IN PARAELECTRIC PHASE OF NANOCRYSTALLINE-TRIGLYCINE SULFATE COMPOSITE

The aim of this work is to clarify dielectric relaxation phenomena in paraelectric phase of composites based on nanocrystalline cellulose and triglycine sulfate. Although the dielectric properties of this material were almost thoroughly investigated, but there has been no study devoted to relaxation anomalies in paraelectric phase. The results showed the presence of Debye-like relaxation at the entire studied frequency range 103 – 106 Hz under a weak electric field of 1 V.m-1 from phase transition temperature in the composite (54 ˚C) to 90 ˚C. In addition, the phenomena were observed at lower frequencies as compared to those of triglycine sulfate single crystals. The results were explained by the assumption based on critical slowing down occurred in the nanoparticles in the composite.

TGS crystal growth below and above Curie temperature (Tc)

Ferroelectric triglycine sulphate (TGS) single crystals were grown by conventional slow cooling and unidirectional solution growth method below and above its Curie temperature (Tc). The evolution of morphology of TGS crystals during conventional growth method was imaged in an online and in-situ manner using laser shadowgraphy, and the growth rates of the crystals along a, b and c-axis were measured in both the temperature regimes. It was found that the growth rates of crystal grown above Tc was higher than that of the crystal grown below Tc. TGS crystals oriented along [010] polar direction and having large (010) habit face were successfully grown below and above its Curie temperature (Tc) by Sankaranarayanan-Ramasamy (SR) unidirectional solution growth method. Time-lapsed photographs of SR growth process were captured at regular interval of time, from where the growth rates of crystals along [010] direction was computed to be 1.5 and 2.2 mm/day for crystals grown below and above Tc respectively. The growth conditions were optimized and the dimension of the grown crystals were 60 mm length and 15 mm diameter for below Tc and 35 mm length and 15 mm diameter for above Tc. Using shadowgraphy, the buoyancy-driven convective patterns around the growing TGS crystals were imaged and the gradual buildup of this activity with the dimension of the crystal and time of the growth was investigated. Shadowgraphy was also used to map the evolution of morphology of TGS crystals growing below and above Tc, and growth rates along the three main crystallographic directions were computed. Mach-Zehnder interferometry was used to image development of concentration gradient in the crystallizer during growth.

Growth of [010] oriented urea-doped triglycine sulphate (Ur-TGS) single crystals below and above Curie temperature (Tc) and comparative investigations of their physical properties

Optically transparent, urea (5 wt%)-doped triglycine sulphate (Ur-TGS) single crystals were grown along polar axis [010] by Sankaranarayanan–Ramasamy unidirectional solution growth method, below and above its Curie temperature Tc = 49.3 °C. Higher growth rate of 5 mm/day was obtained for Ur-TGS crystal grown above Tc. The phase of the grown crystals was confirmed by powder XRD. P–E hysteresis studies show well-saturated hysteresis loop for crystal grown below Tc, and the remnant polarization was 0.60 µC/cm2 with a coercive field of 1.5 kV/cm. The piezoelectric d33 coefficient for Ur-TGS crystal grown below and above Tc was 25 pC/N and 35 pC/N, indicating improved piezoelectric properties of the latter. Dielectric permittivity for Ur-TGS crystal grown above Tc was approximately 10 times higher as compared to the crystal grown below Tc. Improved Vickers microhardness and lower Meyer’s index (n) were observed for Ur-TGS crystal grown above Tc. The etch pit density (EPD) of Ur-TGS crystal grown below and above Tc was 1.8 and 1.1 × 102 dislocations/cm2, respectively, indicating that the quality of the crystals grown above Tc was better than the crystal grown below Tc. The optical transmittance of Ur-TGS crystal grown above Tc was slightly (~ 5%) more than that of crystal grown below Tc. Overall, it is concluded that the higher growth rate and improved physical properties of Ur-TGS crystal grown above its Curie temperature show its suitability for the ferroelectric device applications.

Investigating the Effect of Doping and Sulfuric Acid (H2SO4) on the Growth and Properties of a Triglycine Sulfate (TGS) Crystal

Triglycine Sulfate (TGS) single crystal were grown using a slow evaporation method utilizing deionized water as a solvent at room temperature in two groups. The first group of crystals was grown in a variable pH medium. The second group consisted of crystals doped by Al ions with a varying concentration ratio. It was found that all the TGS crystals grown belong to the monoclinic system, as confirmed through XRD patterns. The results from UV-Vis analysis showed that the crystals grown in the acidic medium were more transparent with increased transmittance to visible light. In addition, the spectral patterns for the as-grown crystals were studied using the FTIR technique, which showed a slight shift, indicating that all the crystals had a similar crystalline structure. The high transmission in the entire visible region for all crystals indicates potential for use of such crystals in (SHG) devices and applications based on UV tunable lasers.

Thermally Stimulated Depolarization Currents in TGS Crystals with Impurities and Radiation Defects under Stepwise Heating

Thermally stimulated depolarization currents (TSDC) of triglycine sulfate (TGS) single crystals, which are pure, $$\gamma$$ -radiated and doped with Cr $${}^{3+}$$ ions, have been studied. When thousandths of a weight percent of interstitial impurities (Cr, Cu, and Fe) are introduced into the lattice of TGS single crystals at the growth stage, the domain structure stabilizes (monodomainization) and the region of the polar phase expands (up to $$T_{\textrm{M}}\sim 110^{\circ}$$ C), while the analogy of the dielectric response at the Curie point $$T_{\textrm{C}}\sim 49.7^{\circ}$$ C is preserved. These effects are observed on the TSDC curves as a peak near $$T_{\textrm{C}}$$ and additional diffuse anomalies near $$T_{\textrm{M}}$$ . Similar phenomena take place in TGS crystals irradiated with $$\gamma$$ -rays in the presence of a polarizing constant electric field. These anomalies are probably due to changes in the energy of protons during their jump-like transitions to a higher energy level in the double-well potential of a hydrogen bond.

Influence of silicon dioxide nanoparticles on dielectric relaxation of triglycine sulfate

This study is devoted to clarifying the influence of silicon dioxide nanoparticles on dielectric relaxation properties of classical ferroelectric triglycine sulfate at frequencies of 102÷107Hz in ferroelectric phase. A mixed composite at different composition mass ratios was synthesized. It was indicated that relaxation frequency of triglycine sulfate inclusion decreased as compared to that of its single crystals and shifted toward lower frequencies with silicon dioxide content increase. The linear dispersion region characteristic for single crystals of triglycine sulfate was expanded. The obtained anomalies were explained based on the assumption of strong interaction between composite components through hydrogen bonds.

Enhanced structural, optical, thermal, mechanical and electrical properties by a noval approach (nanoparticle doping) on ferroelectric triglycine sulphate single crystal

The pristine and AgNP-doped TGS crystals are studied using powder X-ray diffraction, density measurements, solubility studies, UV–Vis analysis, photoluminescence spectroscopic analysis, thermal gravimetric analysis, differential thermal analysis, differential scanning calorimetry, Vicker’s hardness measurements, I–V and impedance measurements. From the XRD studies, TGS crystal formation is confirmed and by further analyzing X-ray diffraction data it is noticed that the incorporation of nanoparticles induce stress in the lattice of TGS crystal, which, in turn, lead to shift in peak positions. Crystal solubility and density values are increased after doping process. From the emission spectrum it is evident that emission intensity increases as the doping concentration increased. The melting point and mechanical hardness of the crystals also showed improvement after AgNP doping. Band gap calculated by Tauc’s relation is found to decrease with increase in doping concentration. Further, electrical studies demonstrated that crystal conductivity is improved as the doping concentration increases.

Применение сканирующей емкостной силовой микроскопии для выявления примесных фаз в сегнетоэлектрике триглицинсульфат

The results of the study of inhomogeneous ferroelectric triglycine sulfate single crystal with a growth periodic impurity structure TGS - TGS + Cr are presented. The impurity distribution was investigated with scanning capacitance force microscopy (SCFM). The peculiarities of the capacitance variations imaging on a doubled and tripled resonant frequency of electrostatic force are considered. The piezoelectric response, surface potential and surface topography were studied. It is shown that capacitive contrast is formed both at the domain boundaries and in the TGS and TGS + Cr bands. It was shown that SCFM allowed one to observe the impurity spatial distribution in the ferroelectric structure at the difference in the chromium concentration about 0.02-0.08 wt%.