By M. Gulam Mohamed, J. Madhavan, M. Vimalan and P. Sagayaraj
Single crystals of organic nonlinear optical material of pure, Cu2+ and Zn2+ doped L-tartaric acid nicotinamide (LTN) crystals were successfully grown by slow evaporation method at room temperature. The cell parameters were estimated by single crystal XRD. The UV-Vis-NIR spectra of pure and doped LTN indicate that these crystals possess a wide optical transmission window from 280 -1500 nm. The SHG efficiencies of both pure and doped LTN crystals were found comparable with KDP. The hardness of these crystals was assessed and the results indicate the minor variations in the hardness value between the pure and doped LTN crystals. The dielectric response of the samples was studied in the frequency region 100 Hz to 5 MHz and the influence of Cu2+ and Zn2+ substitution on the dielectric behaviour had been investigated. The photoconductivity study proves that both pure and doped LTN crystals exhibit positive photoconductivity. The TGA, DTA and DTG curves of doped samples indicate a marginal change in thermal stability when compared with pure LTN. The ESR analysis was carried out for Cu2+ doped LTN and the ‘g’ value was found to be 1.92674.
Key Words : Organic compound, nonlinear optical material, dielectric response, optical transmission.
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