Photoconductivity, dielectric, thermal and mechanical studies on nonlinear optical phasematchable single crystal: 2-amino-4-methylpyridinium 4-nitrobenzoate

Protonated 2-amino-4-methylpyridinium 4-nitrobenzoate compound was synthesised and optical quality NLO single crystals of dimension 5 × 5 × 1 mm³ was grown by isothermal solvent evaporation method. The single crystal X-ray diffraction analysis confirmed the monoclinic system with non-centrosymmetric space group Pc of the grown crystal in which the lattice parameters are a = 10.531 Å, b = 5.012 Å, c = 12.238 Å and also powder X-ray diffraction analysis was performed. The stoichiometric composition of the grown crystal were confirmed using CHN analyser. The FTIR spectrum showed the symmetry of vibrations of molecules in the crystal. Optical transmittance window in the entire visible region will be useful for harmonic generations. At different temperatures, the dielectric constant and dielectric loss were measured with respect to the wide range of frequencies. Mechanical stability of the crystal in (100) and (002) planes were investigated using Shimadzu HMV-2 microhardness analyser and it belongs to soft category. The material was thermally stable up to 222 °C and it was completely converted into volatile substance at 290 °C. The 2-amino-4-methylpyridinium 4-nitrobenzoate crystal exhibited positive photoconductivity and the powder SHG measurement exposed the phasematching ability of the crystal.