Showing papers by "Neetu Ahlawat published in 2019"

Bismuth modified physical and optical properties of barium boro-tellurite glasses

Abstract: A quaternary glass system with compositions TeO2-Bi2O3-B2O3-BaO has been prepared by melt-quench method. The calculated values of density, molar volume and crystalline volume were found to increase with bismuth content. The absorption edge shifts towards lower wavelength side for all the compositions except x = 20 mol%. The optical band gap energy has been evaluated from extrapolation of Tauc’s plot results and Urbach energy has been estimated from linear fitting. The other optical parameters such as refractive index, molar refractivity and metallization criterion have also been discussed.

Non-linear optical properties of SiO2 modified Bi2O3-TeO2-B2O3 glass system

Abstract: In present study, quaternary bismuth borosilicate tellurite glass system with compositions x SiO2-(80-x) Bi2O3-15 B2O3-5TeO2 (x = 0, 5, 10 and 15) has been successfully prepared by melt-quenching technique. The linear refractive index (n0) of prepared glass samples has been observed to decrease with increase in SiO2 content. Third order nonlinear optical properties viz. nonlinear refractive index (n2) and nonlinear absorption coefficient (β) have been estimated by fitting of experimentally observed closed and open aperture Z-scan measurements with theoretical models and found to be dependent on amount of silicate content in studied glass compositions. The third order nonlinear susceptibility (χ(3)) including real and imaginary parts have also been calculated.

Structural, dielectric and ferroelectric properties of substituted BaZrTiO3 lead-free ceramics

Abstract: Lead-free V doped Barium Zirconium Titanate (BZT) ceramic was synthesized by conventional solid-state reaction method. Single phase of ceramic material was confirmed by XRD analysis. Rietveld refinement of XRD data shows that the sample has tetragonal phase having space group P4/mmm. Surface morphology was analyzed by scanning electron microscopy (SEM) shows grains were random and irregular in shape. In the dielectric properties, the effect of frequency and temperature on dielectric constant was investigated. The substitution of V ion on B site decreases the Curie temperature than pure BaTiO3. Theoretical fitting of Curie–Weiss law and Power law of dielectric data was confirmed the diffused phase transition in ceramic material. Doping of V in BZT has ferroelectric character with large value of remnant polarization, coercive field and Pr/Ps ratio. The results shows that the studied composition is suitable for capacitor applications.