Browsing by Author "Dhanasekaran, R"

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    DIELECTRIC AND CONDUCTIVITY PROPERTIES OF FLUX GROWN CE DOPED NBT-BT SINGLE CRYSTALS
    (Elsevier, 2020-04-01) Shanmuga Sundari, S; Binay, Kumar; Dhanasekaran, R
    To study the effect of Ce in the NBT-BT lattice, 0.4 wt% of CeO2 was added to the 0.94(Na0.5Bi0.5TiO3)-0.06BaTiO3, in its morphotropic phase boundary (MPB) composition, and the single crystals were grown by the flux method using Bi2O3 as a flux. The structural studies were carried by the XRD and Raman analyses. The dielectric constants were measured from room temperature to 400 °C for various frequencies in the range of 20 Hz-2 MHz. The anti-ferroelectric temperature region is increasing due to the addition of Ce in the NBT-BT. The maximum value of dielectric loss is also found to decrease from 0.4% to 0.1% due to the Ce addition. The conductivity and impedance analyses were carried out to study the relaxation process of Ce-NBT-BT single crystals.
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    INFLUENCE OF TRANSITION METAL IONS ON MULTIFERROIC PROPERTIES OF LEAD-FREE NBT–BT CERAMICS
    (World Scientific Publishing Company, 2019-12-17) Shanmuga Sundari, S; Dhanasekaran, R
    Using the conventional solid-state reaction method, 0.5wt.% of MnO2-, NiO-, Cr2O3-, Fe2O3- and Co2O3-added 0.94Na0.5 Bi0.5 TiO3 (NBT)–0.06BaTiO3 (BT) ceramics were prepared. The perovskite nature of the prepared ceramics was analyzed by powder XRD and the surface morphology was studied by means of SEM. The dielectric analysis was carried out from room temperature to 350∘ C at various frequencies and the diffusive transition at the dielectric maxima confirmed the relaxor nature of the ceramics. Creation of oxygen vacancies by the possible substitution of ferromagnetic impurities decreased the dielectric constant and piezoelectric constant (d33) The co-existence of ferromagnetism and the ferroelectricity was observed in the Mn, Ni, Co and Cr-added NBT–BT ceramics. The magnetic force microscopy (MFM) analysis was carried out to study the ferromagnetic domains in the prepared ceramic
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    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.
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    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.
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    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.