TGS Crystals Research Articles

An insight into the structure of nanocomposites in porous glasses and their interactions after contact with the environment

Porous sodium borosilicate (SBS) glasses were prepared by conventional charge melting technique and TGS nanocomposites were prepared by introducing TGS crystals from a saturated solution into a pores matrix. The aim of this paper is to clarify the structure and surface changes of the SBS porous glasses before and after introducing TGS crystals. Thermal and dielectric measurements revealed the presence of phase transitions in TGS nanocomposites and confirmed the influence of crystallite size on the phase transition temperature. Powder X-ray diffraction (PXRD), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) revealed the morphological changes of the sample surfaces upon immersion in a TGS saturated solution. Additionally, the atomic ratio of empty porous glasses and TGS-PG nanocomposites was obtained by the XPS analysis. The visible differences in surface properties between empty porous glasses and TGS nanocomposites have been observed and discussed.

Self-organized formation of domain arrays in TGS crystal by moving SPM tip

In this paper, we studied the formation of self-organized domain arrays created by moving biased tip of scanning probe microscope (SPM) in deuterated TGS crystals. The shape of created domains depends significantly on scanning direction and applied voltage. For scanning along c axis, the domain shape drastically changed from arrays to stripe domains at 150[Formula: see text]V. Scanning perpendicular to [Formula: see text] axis led to formation of the array of the dashed domains. Increasing of the dashed domain length leads to change of domain shape from arrays of dashed domains to solid stripe domain. The obtained effect has been considered in terms of the kinetic approach as a result of formation of comb-like domain with charged domain walls in the bulk due to repetitive appearance of the domain spikes. The spontaneous backswitching under the action of the depolarization field leads to the fast growth of the tooth to the surface and results in the transformation of the domain shape. The computer simulation of the nonuniform motion of charged domain wall under the action of depolarization field has been done. The obtained results demonstrate the essential role of screening processes and pave the way for further improvement of domain engineering methods.

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.

Formation of a quasi-equilibrium domain structure of crystals of the TGS group near TC

In the temperature range ΔT ≈ 321 K ÷ 322 K, the kinetics of the nonequilibrium domain structure of triglycine sulphate crystals, both pure and with specially introduced defects, has been studied by means of piezoresponse force microscopy technique. The temporal change in the domain structure as a set of regions with a scalar order parameter of P (r, t) = +1 and −1 for oppositely polarized domains was analysed by the behaviour of the space-time correlation function C(r,t) = ·Р(r,t)Р(0,t)Ò. At different distances from the Curie point Tc, the characteristic length Lc, as a scale measure of the average domain size, increases with time according to the power law Lc(t)~(t−t0)a. A decrease of the exponent a with distance from Tc can be a consequence of the transition of the domain structure of TGS crystals from a non-conservative state to aconservative one.

Theoretical Study of Dielectric Properties in Triglycine Sulphate Crystal

Present paper investigate theoretically dielectric properties such as dielectric constant, soft mode frequency and tangent loss by considering two sub lattice pseudospin, spin-lattice coupled mode model (PLCM) and adding third and fourth-order anharmonic (phonon) and spin-lattice interaction terms and using thermal Green’s function (double time) method expression for dielectric constant, soft mode frequency, and tangent loss is derived for TGS crystal. Model value have been fitted in expression and their temperature dependence have been calculated for TGS crystal. Theoretical results have been correlated with experimental results of (Aravzhi et al 1997), which is approximate close to experimental results.

Unidirectional crystal growth of L-alanine doped triglycine sulphate crystals along [010] polar direction in ferroelectric and paraelectric temperature ranges, and their comparative characterizations

Good quality, large size (010) polar face oriented ferroelectric single crystals of l-alanine doped triglycine sulphate (LA-TGS) were grown by unidirectional solution growth technique in two temperature regimes on either side of its Curie temperature (Tc). The growth conditions were optimized to obtain LA-TGS crystals of length = 40 mm, diameter = 30 mm below Curie temperature (Tc), and length = 50 mm, diameter = 15 mm above Curie temperature, with growth rates of 1.3 and 3.0 mm/day, respectively. Powder XRD was performed for phase confirmation and DTA for phase transition temperature determination, and compared with data of undoped TGS crystal. Crystal grown below Tc has almost same dislocations density, two times higher piezoelectric d33 coefficient, and three times lower dielectric permittivity as compared to the crystal grown above Tc, showing its better device potential. The UV-Vis-NIR transmittance of the two crystals was ≥80 %, showing their good optical quality.

Influence of a static magnetic field on the dielectric properties of triglycine sulfate

The influence of a static magnetic field on the permittivity ε of pure TGS crystals has been studied. There is no of the magnetic effect when the vectors B and PS are collinear, it exists when B and PS are mutually orthogonal and it is greater when B is oriented along a-axis. After the magnetic field is turned off, the values of ε first increase up to the maximum observed of about 30–40 h, and then a long recovery to the initial values of ε occurs. Possible mechanisms of influence of the magnetic field on the studied crystals are discussed.

Growth of single and its electrical properties of ferroelectric TGS crystals

The dielectric properties of TGS crystals and various mol% (1–4 mol%) of amino acid doped TGS crystals at different thicknesses grown at room temperature by using Slow evaporation method. The prepared crystals are used to study the dielectric properties such as dielectric constant and AC conductivity as a function of frequency ranging from 50 Hz to 5 MHz at room temperature are studied for the above mentioned ferroelectric crystals.

Peculiarities of the Dielectric Spectra of Triglycine Sulfate Crystals with a Profile Distribution of Chromium

The temperature evolution of the dielectric spectra of TGS–TGS + Cr crystals (TGS stands for triglycine sulfate) with a periodic distribution of chromium impurity (Cr3+) has been studied in comparison with nominally pure TGS crystals in the frequency range from 10 to 107 Hz upon heating and cooling. It is shown that impurity crystals are characterized by the absence of dielectric dispersion in both measurement modes. An approach is proposed to explain the peculiarities of the dielectric dispersion of crystals with a periodic distribution of chromium impurity from the standpoint of mobile activity of certain elements of the TGS crystal structure.

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.

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.

Quasi-pyroelectricity in the TGS crystal

ABSTRACTIt has been shown that a side electrode perpendicular to the measurement ones can significantly enhance the transverse electric current in TGS. Such a current, measured in a zero external electric field, resembles the classic longitudinal one. However, the amplitude of the transverse current oscillation, observed while cooling and heating the sample, rises much more slowly with the time of the transverse electric field preliminary application. Such exposure to the transverse field is required prior to the measurements for the transverse current to be observed, in a similar way to a longitudinal field that is applied in order to achieve a single domain state before longitudinal pyroelectric current measurements. A huge difference in the time of reaction to the electric fields preliminarily applied in order to achieve the maximum amplitude of the current oscillations in both cases is the evidence that the transverse current cannot be considered to be originated just for geometrical reasons.

Linear and Nonlinear Optical Constants of Potassium Acid Phthalate crystal

Single crystals of potassium hydrogen phthalate (KAP) are grown by solution growth technique. Linear optical constants are evaluated from UV/VIS/NIR spectrum. The Z scan technique is used to elucidate the third order nonlinearity in the material. The results indicate that the compound exhibits reverse saturable absorption (RSA) and self-defocusing performance. The second harmonic generation (SHG) efficiency of the crystal evaluated by Kurtz and Perry technique is compared with that of the standard KDP crystal. Attempt is made to correlate the SHG efficiency with the crystalline perfection in the material. Full Text: PDF ReferencesMiniewicz.A, Barkiewics.S, "On the electro‐optic properties of single crystals of sodium, potassium and rubidium acid phthalates", Adv.Mat.Opt.Elect,2,157(1993). CrossRef Comeretto.D, Rosy.L, "Optical properties of potassium acid phthalate", J.Mat.Res, 12, 1262(1997). CrossRef Krajewski.T, Breczewski.T, "Dielectric and pyroelectric properties of TGS crystals doped with nitroaniline molecules", Ferroelectrics, 25, 547 (1980). CrossRef N. Kejalakshmy, K. Srinivasan, "Growth, optical and electro-optical characterisations of potassium hydrogen phthalate crystals doped with Fe3+ and Cr3+ ions", Opt. Mater. 27,389–394A, (2004). [5] CrossRef Ester. G.R, Price.R, Halfpenny. P.J, "An atomic force microscopic investigation of surface degradation of potassium hydrogen phthalate (KAP) crystals caused by removal from solution", J.Cryst.Growth, 182, 95(1998). CrossRef Hiroyuki Toda, Carl M. Verber "Simple technique to reveal a slow nonlinear mechanism in a z-scanlike n2 measurement", Opt. Lett. 17(19) 1379(1992). CrossRef K.J. Arun, S.Jayalekshmi, "Investigations on the nonlinear optical properties of glycinium oxalate single crystals", Optoelectron. Lett. 7(2), 136, (2011). CrossRef K.J.Arun, S.Jayalekshmi, "Third order nonlinear optical constants of L-alaninium oxalate", Phot. Lett. Poland 7(3), 81-83 (2015) CrossRef

Structural, FTIR and Ferro electric analysis of pure TGS and L-Cysteine doped TGS crystals for infrared device applications

Abstract This paper aims at investigating the line broadening of powder X-ray diffraction peaks as a result of compositional disorder in L -Cysteine doped triglycine sulfate crystals. Various methods such as Williamson-Hall and size-strain plot methods were used in this study. The analysis indicates that L -Cysteine substitution in triglycine sulfate crystals results in anisotropic strain in the crystal. The crystalline quality and cell parameter values were found using XRD analysis. The presence of L -Cysteine in TGS was estimated qualitatively by Fourier transform infrared analysis. The ferroelectric nature of the crystals was identified by P–E hysteresis loop analysis.

Dynamics of Hydrogen Bonds in TGS Crystals Observed by Means of Measurements of Pyroelectric Currents Induced by Linear Changes of Temperature

Dynamics of Hydrogen Bonds in TGS Crystals Observed by Means of Measurements of Pyroelectric Currents Induced by Linear Changes of Temperature

Dynamics of Hydrogen Bonds in TGS Crystals Observed by Means of Measurements of Pyroelectric Currents Induced by Linear Changes of Temperature

Dynamics of Hydrogen Bonds in TGS Crystals Observed by Means of Measurements of Pyroelectric Currents Induced by Linear Changes of Temperature

Piezooptic coefficients and acoustooptic efficiency of TGS crystals

We have determined ten piezooptic tensor components for monoclinic triglycine sulfate crystals, using an interferometric method. Acoustooptic figure of merit has been...

Thermal and surface studies of unidirectional grown nickel sulfate added triglycine sulphate single crystal

Triglycine sulfate crystal added with 0.5 mole% nickel sulfate of 15 mm diameter and 150 mm height has been grown from an aqueous solution using Sankaranarayanan–Ramamasamy (S‐R) method in [001] direction. The grown crystal was studied by various characterization techniques. Thermogravimetry analysis reveals that the NiSO4 added TGS crystal is more thermally stable than pure TGS crystal. The presence of nickel in the TGS‐NiSO4 crystal was confirmed by atomic absorption spectroscopic (AAS) technique and its concentration was found to be 284 ppm. The surface of the grown crystal was investigated using atomic force microscope (AFM). It revealed the surface defects of the doped TGS crystal.

Observation of dynamics of hydrogen bonds in TGS crystals by means of measurements of pyroelectric currents induced by changes of temperature

The study of pyroelectric response of monocrystalline TGS cubic specimens to changes of temperature induced by linear and pulse heating of three mutually perpendicular pairs of cube sides demonstrated a complicated structure of signals. We attribute their forms to the activation of various hydrogen bonds between glycine I, II, III molecules. In the case of pulse heating the pyroelectric signal is observed also in the paraelectric phase. The applied measurement method is relatively simple but precise and can be realized in most of dielectric measurements laboratories.

Dielectric nonlinearity of TGS crystals grown from an aqueous solution with isopropanol

ABSTRACTResults of investigations of the dielectric nonlinearity in TGS crystals with isopropanol and irradiated by X-rays are presented. The formation of internal bias fields has been revealed that are probably related to changes in hydrogen bonds of studied crystals.