Optimization of solution growth and characterization of monomethylurea crystals

Monomethylurea (NMU), a methyl derivative of urea, has been focused recently as promising nonlinear optics (NLO) material. We grew NMU using long thin seeds capped at both ends. This kind of growth was successful, and gave crystals of high structural and optical quality. However, the useful cross section was limited due to the presence of a defected region surrounding the seed. For this reason, we tested an alternative growth method by which larger (25 × 25 mm) cross sections have been obtained. Here we report on this growth procedure, on morphological studies, and on some linear and nonlinear optical characterizations.