Browsing by Author "Shanmuga Sundari, Sankaran"

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STRUCTURAL AND OPTICAL PROPERTIES OF LITHIUM BORATE GLASSES UNDER EXTREME CONDITIONS OF ION IRRADIATION
(IOP Science, 2023-07-05) Karthika S; Asokan K; Marimuthu K; Evangelin Teresa P; Ramcharan, Meena; Durairajan A; MA, Valente; Meena P; Shanmuga Sundari, Sankaran
Lithium borate (LBO) glasses of the composition 10LiO2.90B2O3 were prepared by melt quenching technique and characterized for morphological, structural, and optical properties before and after the exposure to the extreme conditions of 100 MeV Ni ion irradiation. Both the morphological images and structural properties confirm the transformation of LBO glasses from amorphous to polycrystalline nature. This Ni irradiation provides thermal energy that causes the ceramization of glass. The beam interacts with the material where the top layer of the glass remelts, and ultrafast re-solidification occurs after the termination of the ion beams. The Rietveld refinement using the x-ray diffraction data shows that the irradiated LBO possesses a monoclinic crystal structure of lithium pentaborate pentahydrate (B5H10LiO13). The FTIR spectra of Ni ion irradiated glasses show the creation of non-bridging oxygens (NBO) by the formation of BO4 units at the expense of BO3 units. The direct band gap and the Urbach energy of the glasses are affected by the nickel ion irradiation and are in the range 2.73 to 2.55 eV and 0.59 to 0.42 eV. The refractive index also reveals a minor change (1.66 to 1.63). The molar electronic polarizability, metallization criteria, and transmission coefficient were estimated. The coexistence of crystalline and amorphous phases leads to a multiscale phase structure that has multilevel relaxation processes. This is a suitable condition for the improvement of the rheological properties of glass and glass ceramics. Future work involves optimization of the coexistence of these two phases during irradiation.
STRUCTURAL AND OPTICAL PROPERTIES OF LITHIUM BORATE GLASSES UNDER EXTREME CONDITIONS OF ION IRRADIATION
(IOP Publishing Ltd, 2023-07-05) Karthika, S; Asokan, K; Marimuthu, K; Evangelin Teresa, P; Ramcharan, Meena; Durairajan, A; Valente, MA; Meena, P; Shanmuga Sundari, Sankaran
Lithium borate (LBO) glasses of the composition 10LiO2.90B2O3 were prepared by melt quenching technique and characterized for morphological, structural, and optical properties before and after the exposure to the extreme conditions of 100 MeV Ni ion irradiation. Both the morphological images and structural properties confirm the transformation of LBO glasses from amorphous to polycrystalline nature. This Ni irradiation provides thermal energy that causes the ceramization of glass. The beam interacts with the material where the top layer of the glass remelts, and ultrafast re-solidification occurs after the termination of the ion beams. The Rietveld refinement using the x-ray diffraction data shows that the irradiated LBO possesses a monoclinic crystal structure of lithium pentaborate pentahydrate (B5H10LiO13). The FTIR spectra of Ni ion irradiated glasses show the creation of non-bridging oxygens (NBO) by the formation of BO4 units at the expense of BO3 units. The direct band gap and the Urbach energy of the glasses are affected by the nickel ion irradiation and are in the range 2.73 to 2.55 eV and 0.59 to 0.42 eV. The refractive index also reveals a minor change (1.66 to 1.63). The molar electronic polarizability, metallization criteria, and transmission coefficient were estimated. The coexistence of crystalline and amorphous phases leads to a multiscale phase structure that has multilevel relaxation processes. This is a suitable condition for the improvement of the rheological properties of glass and glass ceramics. Future work involves optimization of the coexistence of these two phases during irradiation.
STUDY ON GROWTH, OPTICAL AND DIELECTRIC PROPERTIES OF ‘ND’ DOPED NBT-BT (0.94(NA0.5BI0.5TIO3)-0.06BATIO3) RELAXOR FERROELECTRIC SINGLE CRYSTALS
(Springer Link, 2022-04-01) Shanmuga Sundari, Sankaran; Dhanasekaran, R; Binay, Kumar; Durairajan., A; Valente, M.A; Devaraj Stephen, L
The present work describes the effect of Neodymium (Nd) in the NBT-BT (0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-BT (94/06)) + xNd (x = 0, 0.4, 0.6, 0.8, 1.0 wt%)) crystal grown by flux method. As the concentration of the Nd increases beyond 0.4 wt%, homogeneity of the solution is lost and the multinucleation was observed. Color of the crystal changed from yellow to muddy green and size of the crystals were reduced due to the incorporation of Nd in NBT-BT. Nd completely diffused into the NBT-BT lattice, hence no secondary phase formation was observed in XRD. But the peaks were shifted towards the higher angle side due to the shrinkage of NBT-BT lattice. Optical properties of the crystals are studied using UV–visible and photoluminescence spectra. Except 0.4 wt% of Nd, for all other concentration emission at 1064 nm was observed in the PL spectra. Effect of Nd in dielectric constant and the relaxor properties are discussed in detail.
STUDY ON GROWTH, OPTICAL AND DIELECTRIC PROPERTIES OF ‘ND’ DOPED NBT-BT (0.94(NA0.5BI0.5TIO3)-0.06BATIO3) RELAXOR FERROELECTRIC SINGLE CRYSTALS
(Springer Link, 2022-04-01) Shanmuga Sundari, Sankaran; Dhanasekaran, R; Binay, Kumar; Durairajan, A; Valente, M A; Devaraj Stephen, L
The present work describes the effect of Neodymium (Nd) in the NBT-BT (0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-BT (94/06)) + xNd (x = 0, 0.4, 0.6, 0.8, 1.0 wt%)) crystal grown by flux method. As the concentration of the Nd increases beyond 0.4 wt%, homogeneity of the solution is lost and the multinucleation was observed. Color of the crystal changed from yellow to muddy green and size of the crystals were reduced due to the incorporation of Nd in NBT-BT. Nd completely diffused into the NBT-BT lattice, hence no secondary phase formation was observed in XRD. But the peaks were shifted towards the higher angle side due to the shrinkage of NBT-BT lattice. Optical properties of the crystals are studied using UV–visible and photoluminescence spectra. Except 0.4 wt% of Nd, for all other concentration emission at 1064 nm was observed in the PL spectra. Effect of Nd in dielectric constant and the relaxor properties are discussed in detail.
STUDY ON GROWTH, OPTICAL AND DIELECTRIC PROPERTIES OF ‘ND’ DOPED NBT-BT (0.94(NA0.5BI0.5TIO3)-0.06BATIO3) RELAXOR FERROELECTRIC SINGLE CRYSTALS
(SpringerLink, 2022-04-01) Shanmuga Sundari, Sankaran; Dhanasekaran, R; Binay, Kumar; Durairajan., A; Valente, M A; Devaraj, Stephen. L
The present work describes the effect of Neodymium (Nd) in the NBT-BT (0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-BT (94/06)) + xNd (x = 0, 0.4, 0.6, 0.8, 1.0 wt%)) crystal grown by flux method. As the concentration of the Nd increases beyond 0.4 wt%, homogeneity of the solution is lost and the multinucleation was observed. Color of the crystal changed from yellow to muddy green and size of the crystals were reduced due to the incorporation of Nd in NBT-BT. Nd completely diffused into the NBT-BT lattice, hence no secondary phase formation was observed in XRD. But the peaks were shifted towards the higher angle side due to the shrinkage of NBT-BT lattice. Optical properties of the crystals are studied using UV–visible and photoluminescence spectra. Except 0.4 wt% of Nd, for all other concentration emission at 1064 nm was observed in the PL spectra. Effect of Nd in dielectric constant and the relaxor properties are discussed in detail.
SYNTHESIS AND CRYSTAL GROWTH OF CADMIUM NAPHTHOATE CRYSTAL FOR SECOND ORDER NON-LINEAR OPTICS AND CYTOTOXIC ACTIVITY
(Taylor & Francis Online, 2022) Natarajan, Arunadevi; Ponnusamy, Kanchana; Venkatesan, Hemapriya; Shanmuga Sundari, Sankaran; Mehala, Mayilsamy
A new organometallic crystal diaquo-di(2-hydroxy-1-naphthoate)-cadmium(II) was synthesized by slow evaporation method and characterized for optical, spectral, thermal and biological applications. Single crystal X-ray diffraction revealed that the crystal structure was monoclinic with C2 space group. The crystal perfection and atomic packing of the grown crystal were also analyzed. The presence of functional groups and different vibrational modes were studied from IR spectra. Various decomposition stages and thermal stability of the grown crystal was studied from TG-DTA data. Molar conductance and dielectric of the complex were determined. Energy Band gap, refractive index, skin depth and extinction coefficient of the crystal were calculated from UV-Visible absorption studies and by using Kurtz powder method, the second harmonic generation (SHG) efficiency was examined. In addition, the crystal was investigated for its anticancer activity on lung cancer and breast cancer cells. Using AutoDock Vina software, the binding pattern of the crystal was investigated toward target proteins Leu 862, Glu 793, Trp 796, Gln 858, Tyr 857 and Lys 861.