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Single crystals of tetragonal RCuGa3 (R=La, Pr, Nd and Gd), with BaNiSn3 type structure (space group I4Â mm), have been grown by high temperature solution growth technique using Ga as flux. Their magnetic properties were determined by heat capacity and the measurement of magnetization and electrical resistivity along [100] and [001] directions. Except LaCuGa3, the compounds order magnetically. PrCuGa3 undergoes a ferromagnetic transition with Curie temperature of 4.6Â K. NdCuGa3 shows a bulk magnetic transition at 3.3Â K. The data on GdCuGa3 indicate combined characteristics of spin glass and antiferromagnetic behavior at low temperatures. From the Schottky heat capacity data the crystal electric field level energy spectra have been determined. Further we have performed temperature dependent measurements of electron spin resonance (ESR) on GdCuGa3 between 11Â K and room temperature. The ESR data indicate an enhancement of magnetic fluctuations associated with spin reorientation and both homogeneous and inhomogeneous thermal broadening of the linewidth. |
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We report on a comprehensive study of the magnetization, resistivity and heat capacity on the single crystals of Ce2RhGa12 synthesized using Ga flux. Single crystal X-ray diffraction data confirm the tetragonal Pb/nbm structure of Ce2RhGa12, which is isostructural to Ce2PdGa12. Ce2RhGa12 orders antiferromagnetically at TN = 3.5 K and exhibits anisotropic magnetic behavior, inferred from the magnetization and resistivity data, taken along the two principal crystallographic directions of the crystal, viz., along [100] and [001]. The anisotropic magnetic response of Ce2RhGa12 establishes [001] as the easy axis of magnetization, and a weak meta-magnetic transition is also observed in the magnetic isotherm at 2K along the same axis. A sharp peak in specific heat signals the bulk antiferromagnetic transition at TN = 3.5 K, which shifts to lower temperatures in low applied fields. The electrical resistivity along the two directions shows metallic behavior from 300K down to 1.8K and establishes Ce2RhGa12 as a normal, trivalent cerium compound. |
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Single crystals of Ce2RhGa12 have been synthesized using Ga flux and their structure was determined by single-crystal X-ray diffraction. Ce2RhGa12 crystallizes in the tetragonal space group P4/nbm (No. 125), and is isostructural to Ce2PdGa12, with Z = 2 and lattice parameters a = 6.0405 Å and c = 15.706 Å. Data were collected at the Swiss Norwegian Beam Line at the European Synchrotron Facility, Grenoble, France. Laue diffraction was carried out to confirm the quality of the single crystal and showed well-defined spots and tetragonal symmetry. |
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Single crystals of Hydroxyethylammonium L – tartrate monohydrate [HEALT] have been grown by slow evaporation technique using water as a solvent. The structural and vibrational properties of the crystals were studied. Besides these characterizations ab initio quantum chemical calculations have been performed at HF/6-31G (d) level to derive first order hyperpolarizability. It is shown that the first order hyperpolarizability is found to be 14.2 times more than that of urea. The characteristic vibrational frequencies obtained from polarized Raman spectra in different scattering configurations have been assigned based on the complete factor group analysis. Vibrational analysis of IR and Raman reveals that the charge transfer interaction must be responsible for nonlinear optical (NLO) properties of the present system. The UV absorption measurements have also been carried out to confirm the utility of the material for optical applications. |