Journal of Crystal Growth, Vol.312, No.21, 3171-3177, 2010
Unidirectional growth of L-asparagine monohydrate single crystal: First time observation of NLO nature and other studies of crystalline perfection, optical, mechanical and dielectric properties
L-asparagine monohydrate (LAM), a new amino acid single crystal, was grown by slow evaporation solution technique (SEST) as well as by recently invented Sankaranarayanan-Ramasamy (SR) method in aqueous medium. Using SR method, LAM single crystal of diameter similar to 18 mm and length similar to 52 mm was grown for the first time. The growth conditions were optimized and the maximum growth rate of 1.0 mm per day was observed for the SR crystal. The crystal structure was confirmed by powder XRD. The crystalline perfection was assessed by high resolution XRD and etching studies and found that the quality of the SR crystal is better than the SEST crystal. The UV-vis-NIR spectroscopic study revealed that the SR crystal has good optical transparency than that of SEST crystal. The relative second harmonic generation efficiency was measured and found to be similar to 0.35 times to that of KDP. The laser damage threshold (LDT) was measured and found that the SR crystal has higher LDT value (5.76 GW cm(-2)) than SEST crystal (4.75 GW cm(-2)). The Vickers's microhardness and dielectric studies were also carried out and discussed. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:High resolution X-ray diffraction;Single crystal growth;Growth from solutions;Organic compounds;Nonlinear optic materials