Triglycine Sulpho-phosphate Research Articles

Enhanced ferroelectric properties and crystal structure of TGS0.74P0.26 single crystals

The single crystals of triglycine sulpho phosphate (TGS0.74P0.26) were grown by slow evaporation method with 0.6 M of phosphoric acid in the growth solution. The crystal structure of the grown crystal is refined with 0.74 sulphur and 0.26 phosphorous occupancy with the formula of TGS0.74P0.26 using single crystal x-ray diffraction analysis. The dielectric, ferroelectric and pyroelectric properties of the TGS0.74P0.26 single crystals were investigated. The coercive field (Ec) and internal bias field (Ib) values are 8 kV/cm and 1.4 kV/cm, respectively and these values are found increased compared to the pure TGS and also low dielectric loss was observed. The pyroelectric coefficient of TGS0.74P0.26 crystal is 0.023 µC/cm2/°C and the pyroelectric figure of merit for current, voltage and detectivity are Fi = 105 pm/V, Fv = 0.055 m2/C and Fd = 22 µPa−1/2 respectively. Enhanced ferroelectric properties were observed when compared to the pure TGS crystals. The figure of merit for the detectivity (Fd) shows higher values when compared with that of the well-known materials such as PZT (11.5 µPa−1/2) and other lead free materials such as SBN (7.21 µPa−1/2) and CSBN (12 µPa−1/2). With these excellent properties, the TGS0.74P0.26 single crystal can be a promising material for the pyroelectric detector applications.

Pyroelectric properties of l-alanine and Pt(IV) doped triglycine sulpho phosphate single crystals for pyroelectric infrared detector applications

ABSTRACTSingle crystals of l-alanine doped TGSP and LATGSP/ Pt(IV) were successfully grown from aqueous solutions by slow evaporation technique. Lattice parameters were identified using x-ray diffraction analysis. Dielectric studies were performed at various temperatures at the frequency of 1 kHz. The ferroelectric – paraelectric phase transition temperature was identified using dielectric studies. P-E hysteresis loops were recorded and discussed. Effect of dopant on the internal bias field (Ib) and spontaneous polarization (Ps) of the TGSP single crystals are presented. Pyroelectric coefficient was measured at various temperatures. When compared with the undoped TGSP single crystals, doped single crystals found enhanced pyroelectric properties and suitable for pyroelectric infrared detector applications.

Growth and characterization of pure, chloroacetamide and 4-dimethylaminobenzaldehyde doped triglycine sulphophosphate (TGSP) crystals

Triglycine sulphophosphate (TGSP), chloroacetamide (AC) and 4-dimethylaminobenzaldehyde (DB) doped TGSP crystals were successfully grown from their respective aqueous solutions by slow cooling method. X-ray powder diffraction patterns were collected for pure, AC and DB doped TGSP crystals in order to determine their lattice parameter values. Fourier Transform Infra-Red (FTIR) spectroscopic analysis was carried out to confirm the molecular vibrations of TGSP and the presence of AC and DB in TGSP qualitatively. From the UV–Vis spectroscopic analysis, the absorption range was observed for the grown crystals. From the microhardness test, the Vickers’s hardness of the AC and DB doped TGSP crystals measured on (001) face was found to be higher than that of pure TGSP crystals. The dielectric studies showed the variation of dielectric constant as a function of frequency at room temperature. The thermal behavior of the pure and doped TGSP samples was studied from their thermogravimetric and differential thermal curves.

Growth, spectral studies, thermal and dielectric aspects of l-lysine doped triglycine sulpho phosphate (TGSP) crystals

Single crystals of ferroelectric material triglycine sulpho phosphate (TGSP) have been grown by slow evaporation method. The effect of l-lysine addition on the growth of TGSP crystal has been studied for various concentrations (5, 10 and 20 mol%). Unit cell parameters were determined from powder XRD analysis. Functional groups present in the grown crystal were confirmed from the vibrational frequencies of recorded FTIR and FT-Raman spectrum. The l-lysine doping into the crystal lattice has been qualitatively confirmed by spectral analysis. Thermogravimetric studies confirm that the lysine is incorporated into TGSP crystals. Dielectric studies reveal that the incorporation of lysine into TGSP enhances its dielectric strength.

Nucleation Kinetics, Growth and XRD Studies of undoped and Zinc Sulfate-doped Triglycine Sulpho-Phosphate (TGSP) Crystals

Solubility for various temperatures in the range 30–50°C and induction period measurements for various supersaturation levels were carried out for supersaturated aqueous solutions of undoped and zinc sulfate (ZnSO4)-doped triglycine sulpho-phosphate (TGSP) crystals. It is observed that solubility increases with temperature and induction period decreases with supersaturation levels for all the samples of the work. When TGSP crystals are doped with ZnSO4, the induction period is found to be decreasing and hence the nucleation rate for the doped crystals increases. The critical nucleation parameters were evaluated based on the classical theory of homogeneous nucleation. The calculated values of interfacial tension of the crystal relative to the solution is found to be increasing with doping concentration. Bulk crystals have been grown from the optimized growth parameters. Single crystal X-ray diffraction (XRD) studies on the grown crystals reveal the monoclinic crystal structure. Atomic absorption study (AAS) was carried out to confirm the presence of zinc in the doped TGSP crystals.

Growth, XRD and dielectric properties of triglycine sulpho-phosphate (TGSP) crystals added with magnesium sulfate

Abstract Pure and magnesium sulfate-doped triglycine sulpho-phosphate (TGSP) single crystals were grown by solution method with the slow evaporation technique. Solubility of the samples in de-ionized water was found in various temperatures ranging from 30 to 60 °C. Single-crystal X-ray diffraction (XRD) studies on the grown crystals reveal the monoclinic crystal structure. Atomic absorption study (AAS) was carried out to confirm the presence of Mg 2+ in the grown doped TGSP crystals. Dielectric constant and dielectric loss of undoped and magnesium sulfate-doped TGSP crystals were measured for various frequencies and temperatures. It is observed from the studies that solubility and dielectric properties like dielectric constant and dielectric loss increase when TGSP crystal is added with magnesium sulfate. Thermogravimetric and differential thermal analyses (TG/DTA) on the grown crystals have been carried out. The effect of impurity (magnesium sulfate) on structural, electrical and thermal properties of TGSP crystals has been investigated.

Thermal and electrical properties of Tri Glycine Sulpho Phosphate (TGSP) and L-Asparagine doped TGSP crystals

Tri Glycinsulphate with partial substitution of phosphoric acid, namely Tri Glycine Sulpho Phosphate (TGSP) has been grown by slow cooling method. Habit modifications have been observed with change in the concentration of ortho phosphoric acid (H3PO4). Monoclinic structure of the grown crystals has been confirmed using X-ray diffraction analysis. TGSP crystals doped with L – Asparagine were also grown. The doping effect is qualitatively estimated using FTIR analysis. TGA, DTA studies and dielectric measurements were carried out for pure and L-Asparagine doped TGSP crystals to investigate the thermal and electrical properties of the crystals. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Studies on amino acids admixtured triglycine sulphophosphate crystals

To study the improved characteristics of triglycine sulphophosphate (TGSP) crystals, TGSP crystals mixed with amino acids have been grown by temperature reduction method. Amino acids like alanine, valine and asparagine were selected for doping. The influence of amino acids in the crystal lattice and molecular vibrational frequencies of various groups in the samples have been studied using X-ray powder diffraction and Fourier transform infrared (FTIR) analyses. The thermal behaviour of pure and amino mixed TGSP crystals was studied from the DT and TG analyses.

Dielectric relaxation in pure and irradiated TGSP crystals

Low frequency dielectric measurements in triglycine sulpho-phosphate (TGSP) and gamma-irradiated TGSP crystals were carried out around the ferroelectric to paraelectric phase transition. The dispersion found in the ferroelectric phase cannot be explained only by a Debye equation with a single relaxation time. The ratio of the Curie constants in the para- and ferroelectric phase ( C p/ C f) for the irradiated TGSP samples show that the crystal is partially clamped. The deviations from the typical single relaxation behaviour are more pronounced in irradiated samples clearly indicating the contribution of defects in addition to the impurities to the dynamics of the system.

Ferroelectric studies on amino acids mixed TGSP single crystals

Abstract Amino acids mixed TGS crystals are of interest due to their high pyroelectric coefficient and low dielectric constant. Partial substitution of phosphate has resulted in triglycine sulpho-phosphate (TGSP), a mixed crystal with improved pyroelectric figure of merit. In order to study the effect of amino acids on the ferroelectric properties of TGSP, we have substituted l-alanine (ATGSP), l-valine (VTGSP), l-asparagine (ASP-TGSP) and l-arginine (ARG-TGSP) in pure TGSP The pyroelectric studies and P-E hysteresis measurements carried out on these mixed crystals are reported. A scanning electron microscope in the secondary electron emission mode has been employed to visualize the domains on the mixed crystals.

Growth and surface studies on triglycine sulpho-phosphate (TGSP) single crystals

Growth of triglycine sulpho-phosphate (TGSP) crystals using fabricated and as grown seeds and at three different pH values is reported. Large size crystals with wide plane perpendicular to the ferroelectric axis have been grown by adjusting the pH of the solution and by choosing c-cut seeds. Morphological changes due to pH variations have been identified. Optical microscopic examination of the freshly harvested crystal surface reveals etch pits, spirals and flat topped hillocks. A scanning electron microscope, in the secondary electron emission mode has been employed to observe the cleavage surface and domain structure on TGSP crystal without metallization of the surface. Low accelerating voltage and low probe current have been used to probe the surface to avoid the charging effect. In the absence of charging effect the domains observed are found to be static. There is no change in the domain structure due to phosphate addition.

Growth and characterization of amino acids mixed triglycine sulpho-phosphate single crystals

The growth of amino acids mixed triglycine sulpho-phosphate (TGSP) crystals has been investigated. The crystals were grown by a slow cooling technique. The amino acids mixed were 1-alanine (ATGSP), 1-valine (VTGSP), 1-asparagine (ASP-TGSP) and 1-arginine (ARG-TGSP), the structure of these amino acids are similar to glycine. Changes in the morphology of the crystals with substitution have been identified. The presence of amino acids in the crystal has been identified by FTIR analysis. The relative permittivity decreases in the case of asparagine mixed TGSP crystal (ASP-TGSP). Powder X-ray diffraction shows changes in the peak positions and relative intensity for amino acids mixed TGSP crystals.

Effect of metallic dopants on triglycine sulpho-phosphate single crystals

Abstract In an effort to improve the characteristics of Triglycine sulpho-phosphate (TGSP), metal doping was carried out; sulphates of Mn, Zn, Al and Ni were chosen for doping. Mn and Zn doped TGSP exhibited an enhanced pyroelectric coefficient. The dielectric constant was found to be reduced for all the metal doped TGSP crystals. The peaks of dielectric constant (e′) and loss factor (e″) occur at 52°C for all these specimens. Hysteresis and piezoelectric measurements were also carried out.

Growth and characterization of triglycine sulpho-phosphate mixed crystals

In the present investigation, the changes in the physical properties of triglycine sulphate due to the substitution of phosphate ions in place of sulphate ions in various concentrations have been studied. The pyroelectric measurements made on the samples of TGS and TGSP revealed that phosphate substitution enhanced the pyroelectric figure of merit in the range of compositions studied. The microhardness of TGSP was found to be less than that of TGS.

Vibrational spectra and phase transition in triglycine sulpho‐phosphate

AbstractInfrared and single crystal Raman spectra for various polarization geometries of Triglycine Sulpho‐Phosphate (TGSP) have been recorded and analysed. The bonds of hydrogen atoms in H2SO4 and H3PO4 groups are shown to be weak and the possibility of proton transfer from H2SO4/H3PO4 group is indicated. Two different types of glycinium ions are shown to be present in the unit cell. Temperature dependent Raman spectra of TGSP have been recorded. The phase transition detected around 325 K in TGSP is explained in terms of the flipping motion of the glycinium ion and of attaining a higher crystal symmetry.