A methodical approach to physico-chemical analysis of bis (potassium hydrogen l-malate).malic acid - A semi-organic single crystal for nonlinear optical applications

Bis (potassium hydrogen l-malate).malic acid (PMM), a semi-organic nonlinear optical material was synthesized and crystals were grown from aqueous solution by slow evaporation solution growth technique (SEST). The lattice parameters and space group were confirmed by single crystal X-ray diffraction study. Powder X-ray diffraction study reveals the crystalline nature of the title material. Crystalline perfection of grown crystal was analyzed using high resolution X-ray diffraction rocking curve technique. Fourier transform infrared spectral analysis revealed the vibrational behaviour of chemical bonds of various functional groups. Surface feature of the grown crystal was analyzed through atomic force microscopy. Optical transmittance study shows that the grown crystal has good transparency in the entire visible region. The luminescent property of the title crystal was investigated through photoluminescence spectroscopy. Second harmonic generation efficiency was found using Kurtz-Perry powder technique. The laser-induced surface damage threshold value for the grown crystal as measured using a Nd:YAG laser. Thermal analyses reveal that the crystal is stable up to 230 degrees C. The mechanical strength of the crystal was assessed by Vickers microhardness tester. The dielectric behaviour and its parameters were established through dielectric study. Piezoelectric charge coefficient (d(33)) of the grown crystal was determined using piezoelectric analysis.