Crystal growth, structural, optical, magnetic and thermal properties of pure and thiourea doped L-alanine single crystals for nonlinear optical applications

An organic L-Alanine (LA) and Thiourea doped L-Alanine (TLA) are nonlinear optical single crystals grown in low temperature by solvent evaporation technique at room temperature. The crystallite size of LA and TLA were estimated with the help of powder X-ray diffraction studies with 52.42 nm and 57.34 nm. It has been confirmed by the lattice parameters that grown LA and TLA belong to the system of orthorhombic. Again, the cut off wavelength is doped materials is 240 nm for pure and 302. It is clearly evident from PL Studies that major and sharp emission peak was obtained at 418.9 nm. The third order nonlinear optical susceptibilities of LA and TLA are 0.168 x 10−4 and 2.41 x 10−4 respectively. The sharp endothermic peaks at 284°C and 312° C for LA and TLA, indicates the melting point the crystals. Modes of vibrations and the presence of the functional groups were analyzed by FTIR studies. The estimated coercivity is 6542.9 for LA and 6623.7 for TLA respectively. TLA crystal is the most suitable material for fabrication of nonlinear optical devices.