The Tris Zinc Thiourea Sulphate (ZTS) crystals have been crystallized by slow evaporation technique. The lattice parameters of the grown crystals have been determined by the Energy dispersive x-ray diffraction technique (EDXRD) and the structure has been confirmed. And, the high pressure electrical resistivity study have been carried out on this crystal and the results have been reported here.

Copper tartrate crystals were grown by the gel growth method and characterised by energy-dispersive X-ray (EDAX), scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, Fourier transform infrared, photoluminescence (PL), electron paramagnetic resonance, and low-temperature magnetic studies in the temperature range 300–20 K. The XRD study confirmed the orthorhombic structure of the crystal and the XPS study established the Cu2+ ions in the crystal. UV-vis study deduced the energy gap as 2.15 eV, confirming the semiconducting nature, and Urbach energy as 0.4686 eV. PL showed the presence of Cu2+ vacancy-related defects. Low-temperature magnetic study confirmed the paramagnetic nature in the temperature range 300–77 K, and the crystal showed a weak ferromagnetic signal at 20 K, which is interesting. The magnetic field along with the low temperature caused an ordered spin orientation.

Semiorganic tris thiourea copper (I) chloride (TTCC) single crystals have been synthesized from copper (II) chloride via slow evaporation technique. The stoichiometry of the grown anhydrous complex crystal has been confirmed by elemental CHNS (C, H, N and S) and atomic absorption spectrophotometric (AAS) analysis. The crystal structure with space group has been confirmed by single crystal and powder X‐ray diffraction (XRD) studies. The FTIR study assigned the presence of functional groups and confirmed the co‐ordination of metal ions with thiourea. It also confirmed the transition from Cu2+ to Cu+ when thiourea combined with Copper (II) chloride. The optical transparency of the crystal has been studied by UV‐Vis spectrum and deduced the energy gap. The room temperature Photoluminescence (PL) spectrum reported maximum emission line at 410.92 nm and Stokes shift has been determined as 75 nm or 16.5 eV. Low temperature luminescence study from 300 K to 77 K exhibited three blue emission peaks and one green emission peak. The green emission band has been assigned to recombination of an electron in a shallow trap and Cu2+. Blue emission has been attributed to S2‐ vacancies. The interesting hysteresis loop has been exhibited by the variation of energy gap with low temperature. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

n In c c 3 g v > c In c Q) c t -20 30 40 50 60 70 80 I ) Madras 600 025, India.

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Charge transfer in Ytterbium Selenide ( YbSe ) is analyzed by using experimental and theoretical XRD data. The direction and amount of charge transfer are inferred by plotting and comparing the structure factors of the components. The charge transfer parameters thus obtained are 0.36ē from Yb to Se .

A theoretical study on Eu, Tm and Sm Chalcogenide compounds has been made for determining the electrical transport properties using only two parameters, namely lattice constant and activation energy. The calculated electrical properties such as electrical resistivity, carrier mobility, carrier concentration, carrier effective mass and dielectric constant of different pressures are compared with the available experimental results. They are found to be in good agreement with each other. Then, the limitation of this theoretical study is also discussed.PACS Number(s): 72.15.Eb

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