Complex dielectric, electric modulus, impedance, and optical conductivity of Sr_3−x Pb _x Fe₂TeO₉ (x = 1.50, 1.88 and 2.17)

Abstract

Sr3−x Pb x Fe2TeO9 (x = 1.50, 1.88 and 2.17) were synthesized in polycrystalline form via the solid-state reaction route in air, and were studied at room temperature using powder X-ray diffraction and ultraviolet visible spectroscopy techniques. The crystal structures were resolved by the Rietveld refinement method; x = 1.50 and 1.88 adopt a tetragonal phase (space group I4/mmm) while x = 2.17 adopts a hexagonal phase (space group R 3 ̄ $\bar{3}$ m). The direct bandgap energy (E g) of ∼1.89 eV for (x = 1.50), ∼1.87 eV for (x = 1.88) and ∼1.74 eV for (x = 2.17) was estimated from the Tauc plots of (αhʋ)2 versus photon energy. The Urbach energy (E U) was determined from the plots of logarithmic absorption coefficient versus hυ. Plots of the incident photon energy dependence of optical parameters such as refractive index, extinction coefficient, real and imaginary parts of the dielectric function, dielectric loss, real and imaginary parts of the complex optical conductivity, linear and nonlinear optical susceptibilities, real and imaginary parts of the electric modulus, real and imaginary parts of the impedance were obtained by means of ultraviolet visible spectrophotometer experiments. Additionally, the estimated values of the single oscillator energy, dispersion energy, static refractive index and high-frequency dielectric constant were obtained from the linear portion of the (n 2 − 1)−1 versus (hυ)2 plots using the Wemple–DiDomenico model.

Evaluation of PVC@Silver nanocomposite as sensor for low limit detection of Cadmium by SPR based method

“…9. These spectral attributes were identi ed in regions associated with C-Cl, C-H, and CH 2 stretching vibrations, revealing speci c frequencies: 361 cm − 1 for C-Cl in trans HClC = CHCl in-plane bending mode; 636-695 cm − 1 for C-Cl stretching vibration; 1102-1179 cm − 1 for C-C stretching; 1334-1403 cm − 1 for C-H symmetrical stretching in CH 2 group; 2916 cm − 1 for C-H asymmetrical stretching in CH 2 group; and 2975 cm − 1 for C-H asymmetrical stretching in CH 3 group [71].…”

Structural and Optical Properties of Interfacial InSe Thin Film

“…On the other hand, the value of the refractive index ( n ) can be computed as follows ,− : n = ( 1 + R 1 − R ) + 4 R false( 1 − R false) 2 − k 2 …”

Investigation of optical and dispersion parameters poly vinyl alcohol doped Safranin O dye (PVA/SO) thin film

“…The static refractive index value (n o ) has been estimated by extrapolating the WDD model dispersion equation to (hν→0), which is obtained by [28]:…”