Properties Of Triglycine Sulfate Crystals Research Articles

Ferroelectric properties of triglycine sulfate crystals doped with glycine analogs

Single crystals of ferroelectric triglycine sulfate doped with glycine analogs serine, threonine, lactic acid, and alaninol were grown via the slow solvent evaporation method. The resulting ferroelectric domain structures and polarization–electric field hysteresis loops revealed that these dopants caused triglycine sulfate to form a multidomain structure. This was attributed to hydrogen bonds not being formed, which is significant in polarization reversal, due to the side chains and the substituents of the dopant molecules. Therefore, the dopants did not affect the surrounding dipoles enough to cause cooperative phenomena, such as dipole‒dipole interactions, and do not result in the formation of a single- domain, unlike alanine in our previous study.

Domain structure and properties of triglycine sulfate crystals with profile D,L-α- and L-α-alanine-doped layers

A complex investigation of the domain structure and dielectric properties of triglycine sulfate (TGS) crystals containing profile layers doped with D,L-α-alanine (DLATGS) and L-α-alanine (LATGS) impurities is carried out. The images of the DLATGS and LATGS layers and ferroelectric domains are obtained by piezoelectric force microscopy; the parameters of the domain structure and the degree of unipolarity are determined. It is established that DLATGS layers are multidomain and LATGS stripes are mainly single-domain. The experimental data on the macroscopic dielectric properties of the crystals are compared with the results of a microscopic analysis of the domain structure.

Change in dielectric properties of triglycine sulfate in a constant magnetic field

The effect of a constant magnetic field on the dielectric properties of triglycine sulfate crystals has been investigated. It has been shown that, after the magnetic treatment of the crystal (2 T, 20 min), the hysteresis loop becomes narrower; i.e., the coercive field decreases, and the dielectric permittivity changes in the region of the phase transition. It has been found that the observed effect is anisotropic with respect to the orientation of the crystal in a magnetic field and occurs when the vector of magnetic induction is perpendicular to the polar axis of the crystal. The relative orientation of the magnetic field and the domain structure determines its sign. The doping of the crystal with chromium makes the effect more pronounced and leads to a change in the kinetics of the magnetically stimulated increase in the dielectric permittivity.

Characterization of triglycine sulfate (TGS) crystals grown in water-soluble CdS nanoparticles dispersed in water

Single crystals of Triglycine Sulfate (TGS) were grown in water and also were grown in water-soluble CdS nanoparticles dispersed in water by solution method with slow evaporation technique at room temperature. Watersoluble CdS nanoparticles were synthesized by microwave-assisted solution method using the precursors such as cadmium sulfate, thioglycolic acid and ethylene diamine and they were used for the growth of CdS-added TGS crystals. The grown crystals were characterized by XRD technique, UV-visible spectral studies, measurement of density, microhardness studies, atomic absorptions studies. The effect of Cd 2+ ions on various properties of TGS crystals have been analyszed and reported.

Ferroelectric properties of doped triglycine sulfate crystals grown at negative temperatures

The effect of Cr3+ impurity ions on the dielectric and pyroelectric properties of triglycine sulfate crystals grown at temperatures below 0°C is studied. The Curie temperature TC of the chromium-containing crystals is 0.2–0.4°C lower than that of the impurity-free crystals grown at conventional temperatures. A stable reproducibility of the results of the pyroelectric measurements for the crystals studied is established, which indicates that the polar state in crystals is stabilized by growth defects.

Ferroelectric properties of triglycine sulfate crystals with a nonuniform distribution of chromium impurities

The specific features of the ferroelectric behavior of triglycine sulfate crystals with a nonuniform distribution of chromium impurities are analyzed. It is demonstrated that the dielectric hysteresis loops of the samples exhibit large shifts both along the polarization and electric field directions. The results obtained are well explained within the phenomenological approach with due regard for the gradient term in the expansion of the free energy. It is established that the unipolarity coefficient and the pyroelectric signal of nonuniform crystals remain virtually unchanged in multiple heating-cooling cycles.

Effect of amino acid doping on the growth and ferroelectric properties of triglycine sulphate single crystals

Effect of amino acids ( l-leucine and isoleucine) doping on the growth aspects and ferroelectric properties of triglycine sulphate crystals has been studied. Pure and doped crystals were grown from aqueous solution by low temperature solution growth technique. The cell parameter values were found to significantly vary for doped crystals. Fourier transform infrared analysis confirmed the presence of functional groups in the grown crystal. Morphology study reveals that amino acid doping induces faster growth rate along b-direction leading to a wide b-plane and hence suitable for pyroelectric detector applications. Ferroelectric domain structure has been studied by atomic force microscopy and hysteresis measurements reveal an increase of coercive field due to the formation of single domain pattern.

Dielectric properties of triglycine sulfate crystals with defects at low and infralow frequencies

Dielectric responses of several crystals in ultraweak measuring fields at low and infralow frequencies are compared, namely, of nominally pure, Cr-and Lα-alanine-doped triglycine sulfate (TGS) crystals and TGS + Cr3+ crystals irradiated with X-rays. It is shown that dopant-induced bias fields give rise to crystal unipolarity, suppress the domain contribution to their dielectric response, and diffuse the phase transition. It is established that X-ray irradiation of the crystals results in “radiation annealing” of TGS + Cr3+ crystals, which increases their permittivity and diminishes diffusion of the phase transition.

Water-soluble ferroelectric crystals with inhomogeneous impurity distribution

Stabilization of the unipolar state via the formation of inhomogeneous impurity distribution in crystal bulk is considered. Possible growth of crystals with stable characteristics is demonstrated on triglycine sulfate (TGS) crystals with a regular inhomogeneous impurity distribution. The properties of TGS crystals with an inhomogeneous distribution of chromium ions grown above and below the Curie temperature T C are studied. Inhomogeneous TGS crystals of three types are obtained: type-I crystals with a smooth variation of the concentration gradient along the growth direction, type-II crystals with a periodic layer variation of the impurity concentration, and type-III crystals with a sawtooth-like variation of the impurity concentration along the sample length. The TGS crystals with the regular inhomogeneous impurity distribution in the ferroelectric phase are characterized by higher values of the internal bias field E b , unipolarity coefficient k, and pyroelectric coefficient γ than the inhomogeneous crystals in the paraelectric phase and the crystals with the statistic impurity distribution grown by the conventional method.

Morphological changes of L-asparagine doped TGS crystal

This paper discusses the growth and properties of Triglycine Sulphate Crystals (TGS) and with L-Asparagine. Doped single crystal was grown by slow-cooling solution growth technique. TGS crystals with 10 wt% of L-Asparagine exhibited prominent morphological changes in the (101) and (001) planes. Lattice parameter values were determined by powder X-ray diffraction analysis. Incorporation of L-Asparagine in TGS crystals has been qualitatively estimated and confirmed by Fourier Transform Infrared (FTIR) spectra. Micro hardness studies also performed for the pure and doped crystals. A morphology diagram is given.

Higher order ferroic properties of TGS monocrystals

It follows from symmetry consideration that ferroelectrics should possess ferroelastoelectric properties also. The form of ferroelastoelectric domains of uniaxial «pure» ferroelectric triglycine sulphate (TGS) is determined. The effects of the influence of uniaxial mechanical pressure on dielectric hysteresis loops of TGS single crystals are observed. Pressure applied in y-direction decreases height of saturated hysteresis loops (case of high ac-voltage) and increases height of non-saturated loops (case of low ac-voltage). In both cases coercitive field decreases with the pressure increase. Such a behavior may be connected with ferroelastoelectric properties of TGS crystals when uniaxial pressure produces favorable conditions on the domain wall motion.

Dielectric properties of triglycine sulphate crystals admixtured with L-threonine

Abstract The influence of L-threonine admixture on the dielectric properties of TGS crystals (LTTGS) was studied. With increasing concentration of the admixture in the solution from which the crystals were grown, their maximum permittivity and spontaneous polarization were found to decrease, their Curie point was found not much different from that for pure TGS crystals (322K), the coercive field and bias field increased. The domain structure of the obtained crystals was also studied by the liquid crystal method.

The effect of dopants on the growth and properties of TGS crystals

Triglycine sulphate (TGS) crystals were grown from pure and doped solutions. The results referring to the influence of the dopants on the growth, the domain structure, the lattice parameters and the different dielectric parameters are reported and discussed.

Investigation of pyroelectric properties of triglycine sulphate crystals doped with metal ions

Abstract Pyroelectric properties of triglycine sulphate (TGS) single crystals doped with Co, Cu, and Tl ions were studied. In crystals containing less than 5 × 10−5 wt% of impurities, an increase of pyroelectric coefficient and magnitude of reorienting polarization is observed as compared with those in pure TGS. Larger doping concentrations lead to decrease of these parameters. Anomalous pyroelectric hysteresis loops are observed in some cases. Thermal Barkhausen effect (TBE) was also studied. On this basis it was found that the temperature of most intense depoling drops for doped TGS crystals in comparison with pure ones. The nature of observed concentration dependence of pyroelectric properties is interpreted on the same ground as the radiation-induced changes in ferroelectric properties. TBE is analyzed in terms of depolarizing fields of bounded charges, occurring due to temperature gradients in the crystal.