Ferroelectric Triglycine Sulfate Crystal Research Articles

Magnetically Induced Effects in Ferroelectric Triglycine Sulfate Crystals with Chromium Impurity

Magnetically Induced Effects in Ferroelectric Triglycine Sulfate Crystals with Chromium Impurity

Magnetically Induced Effects in Ferroelectric Triglycine Sulfate Crystals with Chromium Impurity

The influence of a permanent magnetic field on macro- and nanoscopic properties of triglycine sulfate (TGS) crystals with impurity chromium (TGS-Cr) has been investigated. This work continues the previous studies of magnetically induced effects in ferroelectrics. A specific feature of TGS crystals is the presence of a nanoscale relief on a polar (010) cleavage; this nanorelief is a qualitative characteristic of the crystal defect structure. It is shown that the exposure of a crystal in a magnetic field of 2 T leads to a change in its dielectric properties, accompanied by a long-term transformation of the nanorelief. The results obtained are indicative of a magnetically induced change in the defect crystal structure. A qualitative difference is found between the magnetically induced effects in TGS-Cr crystals and undoped TGS crystals. The relationship between the magnetically induced effects and structural defects is discussed.

Dielectric Spectra of TGS + Сr Crystals in the Vicinity of Phase Transition

Dependencies of the complex permittivity of chromium-doped ferroelectric triglycine sulfate crystals (TGS + Cr) have been measured using dielectric spectroscopy method in a frequency range of 1–107 Hz and a temperature range of 23–60°C upon heating and cooling. The dielectric spectra are analyzed by considering the temperature‒frequency dependences of the real (e') and imaginary (e") parts of permittivity in the immediate vicinity of the phase transition using the dynamic conductance model and taking into account resonance processes. Good agreement between calculated and experimental data is obtained for the dielectric response of TGS + Cr crystal near the Curie temperature.

In Situ Observation of the Phase Transition of a Ferroelectric Triglycine Sulfate Crystal by Piezoresponse Force Microscopy

The second-order phase transition in a ferroelectric triglycine sulfate crystal is studied in situ by piezoresponse force microscopy. For the first time, the formation of a metastable one-dimensional quasiperiodic polarized structure is observed in the critical region of the phase transition, within one degree near the Curie temperature. Via image processing, the temperature dependence of the parameters of the quasiperiodic structure is studied. At a temperature exceeding the phase-transition point by one degree or more, the usual domain structure is formed, the width of the domains and the spread of the widths with respect to their mean value increase significantly.

Study of the quasi – Periodic one dimensional domain structure near TC of TGS crystal by PFM and hybrid PFM methods

The phase transition of ferroelectric triglycine sulfate crystal (TGS) was studied in situ with the method of the piezoresponse force microscopy in the contact and hybrid modes. The formation of the metastable quasiperiodic domain structures was observed in narrow temperature range near phase transition. Two-dimensional correlation functions calculation allows to determine structure period and to analyze domain dynamics near Curie temperature TC.

Dynamic electrophysical characterization of rubidium polytungstate, Rb4W11O35, under fast humidity impact

The electrophysical reaction of rubidium polytungstate Rb4W11O35 (RWO) on fast humidity impact has been investigated by studying the influence of wet air pulse of 1–3 s of duration on the peculiarities of dynamic current–voltage (I–V-) and charge-voltage (Q–V-) loops and transient current–time (I–t-) curves. The revealed peculiarities of hysteretic I–V- and Q–V-loops and I–t-curves for RWO subjected to humidity impact were compared with similar ones observed for water damaged hydrogen-bounded ferroelectric triglycine sulphate (TGS) crystals. The obtained data indicate at least two possible scenarios of polar reaction on the humidity impact, namely protonic/ionic space charge transfer and ferroelectric-like reversible polarization in surface RWO conglomerate disturbed by dipolar H2O adsorbate. Owing to a high surface activity the RWO can be considered as one of promising materials for creating humidity sensitive elements of environment monitoring systems. The direct humidity-to-frequency conversion was realized using LC resonance or RC-relaxation generating units.

Effect of phosphorous on the growth, optical, mechanical and thermal properties of L-alanine crystals

Single crystals of L-alanine were grown from aqueous solution with a small amount of orthophosphoric acid (H 3 PO 4 ). The single crystal X-ray diffraction (XRD) analysis was employed to identify the cell parameters. The grown crystal was characterized by Energy Dispersive X-ray (EDX) spectrum. The UV-visible transmittance was recorded. The presence of a functional group was confirmed by FTIR analysis. The TGA/DTA studies showed the thermal properties of the crystals. The mechanical strength was analyzed by measuring microhardness of the grown compounds. The second harmonic generation of grown crystals was confirmed by the Kurtz-Perry method using an Nd:YAG laser. Full Text: PDF References D.S. Chemla, J. Zyss, (Eds.), Nonlinear Optical Properties of Organic Molecules and Crystals (Academic Press, Orlando, New York, 1987). C. Razzetti, M. Ardoino, L. Zanotti, M. Zha, C. Paorici, "Solution Growth and Characterisation of L-alanine Single Crystals", Cryst. Res. Technol. 37, 456 (2002). CrossRef E. Ramachandran, S. Natarajan, "Synthesis of L-valine crystals", Cryst. Res. Technol. 44, 641 (2009). CrossRef K. Srinivasan, "Growth of non-linear optical ?-glycine single crystals and their characterization", J. Arumugam, Optic. Mater. 30, 40 (2007). CrossRef Sd. Z. Ali Ahamed, G.R. Dillip, L. Manoj, P. Raghavaiah, B. Deva Prasad Raju, "Growth and characterization of new NLO material: L-serine sodium nitrate", Phot. Letters Poland 2(4), 183 (2010). CrossRef S. Dhanuskodi, J. Ramajothi, "Crystal growth, thermal and optical studies of L-histidine tetrafluoroborate: A semiorganic NLO material", Cryst. Res. Tech. 39, 592 (2004). CrossRef R. Ittyachan, P. Sagayaraj, "Growth and characterization of a new promising NLO L-histidine bromide crystal", J. Cryst. Growth 249, 557 (2003). CrossRef M. Lydia Caroline, R. Sankar, R.M. Indirani, S. Vasudevan, "Growth, optical, thermal and dielectric studies of an amino acid organic nonlinear optical material: l-Alanine", Mater. Chem. Phys. 114, 490 (2009). CrossRef G. Ravi, S. Anbukumar, P. Ramasamy, "On the growth and characterization of mixed crystals of the triglycine sulphate family", J. Cryst. Growth 133, 212 (1993). CrossRef N. Nakatani, M. Yoshio, "Crystal Form of Phosphoric-Acid-Doped Triglycine Sulfate", Jpn. J. Appl. Phys. 35, L 508 (1996). CrossRef N. Nakatani, M. Yoshio, "Doping of Phosphoric Acid into Ferroelectric Triglycine Sulfate Crystal", Jpn. J. Appl. Phys. 35, 5752 (1996). CrossRef A. Saxena, V. Gupta, K. Sreenivas, "Characterization of phosphoric acid doped TGS single crystals", J. Cryst. Growth 263, 192 (2004). CrossRef M. Anbuchezhiyan, S. Ponnusamy, C. Muthamizhchelvan, C.C. Kanakam, S.P. Singh, P.K. Pal, P.K. Datta, "Etching, micro hardness and laser damage threshold studies of a nonlinear optical material L-valine", Eur. Phys. J. Appl. Phys. 58, 10201 (2012). CrossRef K. Seethalakshmi, S. Perumal, "Studies on growth, structure and optical studies of undoped and KBr doped Lalanine single crystals", Recent Research Sc. Techn. 4(6), 13 (2012). DirectLink Ferdousi Akhtar, Jiban Podder, "A Study on Growth, Structural, Optical and Electrical Characterization of L-alanine Single Crystal for Optoelectronic Devices", Research J. Physics 6(2), 31 (2012). CrossRef K. Sangwal, B. Surowska, "Study of indentation size effect and microhardness of SrLaAlO 4 and SrLaGaO 4 single crystals", Mater. Res. Innovat. 7, 91 (2003). DirectLink S.K. Kurtz, T.T. Perry, "A Powder Technique for the Evaluation of Nonlinear Optical Materials", J. Appl. Phys. 39, 3798 (1968). CrossRef

Influence of the electrical conductivity on dielectric characteristics of a triglycine sulfate crystal over a wide frequency range

The dielectric spectra of ferroelectric triglycine sulfate crystals were measured in the frequency range from 10 to 1011 Hz and analyzed based on the concept of a significant contribution of the conductive component to the dielectric response of ferroelectrics. Images of lenticular ferroelectric domains in sulfate triglycine crystals were obtained using scanning spreading resistance atomic force microscopy, and background currents (10−14 A) and currents at domain walls (10−12 A) were measured. It was shown that the inclusion of the contribution from the electrical conductivity to the dielectric spectra is in good agreement with the experimental data and provides additional information on the temperature dynamics of the domain structure.

A comparative study of ferroelectric triglycine sulfate (TGS) crystals grown by conventional slow evaporation and unidirectional method

Unidirectional 〈010〉 TGS single crystal of diameter 35mm and length 80mm was grown by Sankaranarayanan–Ramasamy (SR) method. Nearly two times higher d33 value has been obtained for the SR grown TGS crystal compared to conventional grown TGS. The etch pit density of SEST and SR method grown TGS crystal is 2.1×102cm−2 and 1.5×102cm−2 respectively. The values of hardness were found to be 152kg/mm2 for SR grown TGS and 108kg/mm2 for SEST grown TGS crystal. The average laser damage threshold obtained on the SEST grown TGS crystal was 29mJ/cm2 whereas a high damage threshold of 39mJ/cm2 was obtained for the SR grown crystal. The SR method grown TGS has 5% higher transmittance as against conventional method grown crystal. Dielectric study showed higher dielectric permittivity and lower dielectric loss in SR grown TGS crystal.

Nanorelief of the natural cleavage surface of triglycine sulphate crystals with substitutional and interstitial impurities

Ferroelectric triglycine sulphate crystals (TGS) with substitutional (LADTGS+ADP, DTGS) and interstitial (Cr) impurities have been studied by atomic-force microscopy, X-ray diffraction, and X-ray fluorescence. The nanorelief parameters of the mirror cleavage TGS(010) surface have been measured with a high accuracy. A correlation between the crystal defect density in the bulk and the cleavage surface nanorelief is revealed at the submicrometer level.

8MeV electron irradiation effect on the dielectric and optical properties of iminodiacetic acid doped ferroelectric triglycine sulphate crystals

Abstract Single crystal of iminodiacetic acid (5 mol%) doped Tri Glycine Sulphate (IDATGS) was grown by slow evaporation from its aqueous solution at constant temperature, using solution growth method. The dielectric constant ( e ′) and pyroelectric current ( I P ) were measured over the temperature range of 30–60 °C in the ferroelectric direction. The measured values of e ′ and I P were found to be smaller compared to pure triglycine sulphate (TGS) crystal parameters. But increased transition temperature was observed for doped crystals. Curie Weiss constants C P and C f in the paraelectric and ferroelectric phases were also determined. The doped crystal was irradiated with graded dosages from 5 to 80 kGy of electron beam from 8 MeV Microtron at room temperature and radiation effects on optical and dielectric properties were studied. The UV–Vis absorption spectrum indicates that the UV lower cutoff shifts towards the higher wavelength region (red shift) and the optical band gap is found to be decreasing with the increase of electron dose. It is also observed that the electron irradiation effects in pure and doped TGS were found to be long lasting. The dielectric study shows that there is a gradual reduction in dielectric constant at T C and shifting of Curie temperature towards lower temperature region with the increase in electron radiation dose. The material figures of merit were found increased after the crystal was irradiated. Induced changes in the physical and optical properties due to irradiation may help one to tailor the device quality and characteristics.

Ferroelectric triglycine sulphate crystals with a profile distribution of chromium impurity

Some features of the ferroelectric behavior of triglycine sulphate crystals with a nonuniform distribution of chromium impurity have been considered. The dielectric hysteresis loop of the samples is characterized by a large shift along both the polarization axis and the electric field direction. The results are explained well within the phenomenological approach with allowance for the gradient term in the expansion of free energy. It is established that the unipolarity coefficient and pyroelectric signal of inhomogeneous crystals barely changes during multiple heating-cooling cycles.

Temperature dependence of the effective anchoring energy for a nematic-ferroelectric interface

Specific features of the anisotropic interaction between a nematic mixture and a polar surface of a ferroelectric triglycine sulfate crystal have been studied over a wide temperature range including the substrate's Curie point T(c). The mixture was composed of two nematic liquid crystals, 60% of p-methoxybenzylidene-p-n-butylaniline (MBBA) and 40% of p-ethoxybenzylidene-p-n-butylaniline (EBBA), and doped with a small amount of a dichroic dye. The temperature dependence of the polarized components of optical density D(j) of the dye absorption band for the nematic and isotropic phases of the MBBA+EBBA mixture has been obtained using polarization optic techniques. The temperature-induced structural changes in the nematic layer near T(c) were found to be related to the changes in the orientational part of the tensor order parameter Q(ik). The experimental data have been interpreted using the model, in which the dispersive van der Waals forces of the substrate stabilize the planar orientation of the nematic in the bulk competing with the short-range anchoring forces in the vicinity of T(c). At the same time, the anisotropic part of the surface energy has two terms with the orthogonal easy axes. The nature of the surface electric field and its effect on the director alignment at the interface have been clarified. Taking into account the known relation between anchoring strength and the nematic order parameter, the effective anchoring energy w(eff) for the studied system has been determined as a function of temperature.

Pyroelectric Properties of Some Compounds Based on Protein Aminoacids

Protein aminoacid-based compounds were synthesized, and their single crystals were grown. The dielectric and pyroelectric properties of the crystals were studied in the temperature ranges 80–340 and 140–340 K, respectively. It was established that three of the compounds studied (L-His(H3PO4)2, L-TyrHCl, L-Ala2H3PO3 · H2O) are linear pyroelectrics, with their room-temperature pyroelectric figures of merit being close to those of ferroelectric triglycine sulfate crystals.

Observation on Nonlinear Dynamical Fluctuation in Ferroelectric Triglycine Sulfate Crystal by Measuring Time Series of Electric Property

Time series of electric property for the triglycine sulfate crystal were measured at temperatures, 50 K≤ T ≤324 K on heating. The time series data were analyzed by both statistical and non-linear d...

Internal bias field in TGS crystals doped with different impurities

The influence of an internal bias field formed by impurity ions of heavy metals and alpha-alanine molecules on the dielectric nonlinearity and emission properties of ferroelectric triglycine sulfate crystals has been studied. It is shown that a role of defects increases near the phase transition, which manifests itself in a decrease in the maximum values of the effective permittivity and an increase in the emission current with increasing impurity concentration.

Thermally stimulated electron emission from chromium-doped triglycine sulfate in the paraelectric phase

Thermally stimulated electron emission from a ferroelectric chromium-doped triglycine sulfate (TGS) crystal was experimentally observed to occur in a temperature range 6 K above the Curie point from samples heated at a relatively high rate. Increasing the heating rate q was shown to cause the emission current density to increase throughout the temperature range studied. The emission onset temperature in chromium-doped TGS depends only weakly on the rate q and is close to that for pure TGS, and the emission cutoff temperature grows monotonically with q at comparatively low heating rates and stabilizes at high q. At the same time, the interval of emission extension into the paraelectric phase here is about one half that for pure TGS heated at the same rate. The specific features of emission observed for this crystal can be assigned to relaxation of the charges screening the spontaneous polarization. The lower emission cutoff temperature for the chromium-doped TGS compared to that for pure TGS is accounted for by the shorter Maxwellian relaxation time in the doped crystal.

Selective Effect of Weak Magnetic Field on Triglycine Sulfate Crystal

Selective effect of weak permanent magnetic field on nominally pure ferroelectric triglycine sulfate crystal has been observed for the first time. The prolonged changes of permittivity and Curie point were observed after short-term treatment of the crystal in a narrow interval of magnetic field ∼0.1 T . The effect is explained by magnetic field assisted depinning of domain walls from point defect clusters by spin-depended mechanism similar to depinning of dislocations from paramagnetic obstacles in magnetoplasticity. The point defect clusters are assumed to be H-bonded ones.

Formation of an internal bias field in chromium-and L, α-alanine-doped triglycine sulfate crystals

The unipolar state of a chromium-and L, α-alanine-doped ferroelectric triglycine sulfate (TGS) crystal has been studied. The experimental data on the distribution of internal bias fields with respect to a seed are considered. The possible mechanisms of the formation of an internal bias field during the growth of TGS crystals with a low impurity concentration are considered.

Temperature-induced orientational transition of nematics on the surface of a ferroelectric crystal

A temperature-induced orientational transition is investigated in a mixture of nematic liquid crystals on the surface of a cleavage of a ferroelectric triglycine sulfate crystal. The transition has been observed by the variation of the polarized absorbance components of a dye introduced into the nematic matrix with increasing temperature. The reorientation of molecules in the liquid crystal volume confined by solid walls is due to competition between dispersion and polar forces at the surface and the decrease in the electric field of the substrate up to its complete disappearance at the ferroelectric Curie point.