Studies on synthesis, structural, thermal, optical, spectral and mechanical properties of an inorganic strontium nitrate NLO single crystal

Abstract

An inorganic NLO single crystal of strontium nitrate (SrN) was successfully grown from an aqueous solution, by slow evaporation technique at ambient temperature. Good transparent SrN crystals were obtained within 2 weeks. Various characterizations were carried out to ensure the application of the grown material. Single crystal XRD study reveals that the crystal shows a cubic structure with a centrosymmetric Pa3¯ space group. The crystalline nature of the compound was confirmed by powder X-ray diffraction. The unit cell dimension of the SrN crystal was found to be, a=b=c=7.8220 Å, and the axial angle is α =β=γ=90°. The average crystalline size of the material was 52 nm. The various functional groups associated with grown crystals have been characterized by FTIR and FT-Raman spectroscopy studies. The lower cut-off wavelength is found to be 320 nm and the band gap energy of the SrN crystal was 3.9 eV. The synthesized crystal exhibits 84% transmittance in the visible region. The grown crystals were thermally stable up to 135 °C. Various mechanical parameters such as microhardness (Hv), work hardening coefficient (n), elastic stiffness (C11), and yield strength (σy) of the grown material have been carried out by the indentation method. The nonlinear refractive index (n2), nonlinear absorption coefficient (β), and third order nonlinear susceptibility (χ(3)) were studied using the Z-scan technique, which involves open and closed aperture measurements with a continuous wave laser of 632.8 nm.